Washington (CNN)With tensions flaring between Russia and the West, Vice President Joe Biden blasted Russian President Vladimir Putin Wednesday and said that the White House is still mulling sending arms and equipment to besieged Ukrainian troops.
Biden criticized Putin for what he called "brutal aggression" in Ukraine, and said the Russian president was also responsible for "aggressive repression at home."
Top military brass, including Defense Secretary Ash Carter and Chairman of the Joint Chiefs of Staff Gen. Martin Dempsey, have expressed support for transferring more weapons to Ukraine as it battles Russian-backed separatists in the eastern part of the country.
But President Barack Obama, faced with skepticism from European partners, has so far resisted supplying Ukrainians with lethal aid. Some American officials have expressed concern that sending arms could escalate the crisis into a proxy war with Putin and have favored instead ramped-up financial assistance.
Later on Wednesday, the U.S. announced an additional $18 million in humanitarian assistance for Ukrainians, bringing the total American contribution to $61 million. The State Department said 5 million people inside Ukraine need humanitarian aid, including disabled and elderly Ukrainians.
Biden, saying the debate over supplying Ukraine with weapons was "worth having," didn't shy away from using tough words against Putin in his address Wednesday to the Brookings Institution in Washington.
Calling Putin's hard-fisted approach toward dissidents and gays "bullying," Biden said "Putin's vision has very little to offer the people of Europe, or for that matter the people of Russia, other than myths and illusions."
But he noted that Russia and the U.S. have worked as partners in the ongoing negotiations with Iran over its nuclear program and said the U.S. was continuing to offer Putin "off ramps" to deescalate the Ukraine crisis.
"We're not looking to embarrass him," Biden said. "We're not looking for regime change. We're not looking for any fundamental alteration of the circumstances inside Russia. We're looking for him to, in our view, act rationally."
Photos: Russian President Vladimir Putin
Russian President Vladimir Putin is a popular but polarizing figure who has dominated Russian politics for more than a decade. Click through to see images of his life and career.
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Photos: Russian President Vladimir Putin
Putin, bottom, wrestles with a classmate in St. Petersburg, Russia, in 1971.
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Putin poses with his parents, Vladimir and Maria, in 1985.
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From 1991 to 1994, Putin served as the chairman of the Foreign Relations Committee of the City Council in St. Petersburg. Before becoming involved in politics, he served in the KGB, a Soviet-era spy agency, as an intelligence officer.
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Photos: Russian President Vladimir Putin
Russian President Boris Yeltsin, right, shakes hands with Putin during a farewell ceremony at the Kremlin in Moscow in December 1999. Putin rose quickly through the political ranks, becoming the second democratically elected president of the Russian Federation in 2000.
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Photos: Russian President Vladimir Putin
President-elect Putin watches the tactical exercises of Russia's Northern Fleet in the Barentsevo Sea in April 2000.
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Putin takes the presidential oath next to Yeltsin in May 2000.
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Putin dances with a young girl in Kazan, Russia, while taking part in mid-summer festivities in June 2000.
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Putin and U.S. President Bill Clinton talk in Moscow in June 2000.
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Putin meets Pope John Paul II in Rome in June 2000.
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Putin speaks to his wife, Lyudmila, as they pose in front of the Taj Mahal in India in October 2000.
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Putin shakes hands with famous Russian gymnasts Alina Kabayeva, center, and Svetlana Khorkina in March 2004.
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Putin attends an inauguration ceremony for President-elect Dmitry Medvedev in May 2008. Putin was constitutionally obliged to stand down as President, but he stayed close to power, becoming Prime Minister.
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Photos: Russian President Vladimir Putin
This image, supplied by Time magazine, shows Putin on the cover after being named the magazine's 2007 "Person of the Year."
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Putin skis in Krasnaya Polyana, Russia, in February 2008.
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Putin shakes hands with Libyan leader Moammar Gadhafi in November 2008.
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Putin vacations outside the town of Kyzyl in Southern Siberia in 2009. Over the years he has earned a reputation as a "strongman," declaring a crackdown on Chechen militants a priority in his first presidential term.
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U.S. President Barack Obama meets Putin at his home in Novo Ogaryovo, near Moscow, in July 2009. Putin said Russia was pinning its hopes on Obama to revive ties with the United States.
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Medvedev and Putin ski together in Krasnaya Polyana in January 2010.
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Putin takes part in a judo training session at a sports complex in St. Petersburg in December 2010. Putin holds a black belt in judo.
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In April 2011, Putin attends the first Global Ministerial Conference on Healthy Lifestyles and Noncommunicable Disease Control. The event was held in Moscow.
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Putin receives a medical consultation in August 2011 during a visit to the Smolensk Regional Hospital in Russia. Putin said he hurt his shoulder during morning judo practice.
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Putin speaks to supporters at a Moscow rally in February 2012. He won the presidential election one month later with just under 65% of the vote. Former President Medvedev became his Prime Minister.
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During a massive rally of his supporters in Moscow, tears run down Putin's face in March 2012 after he was elected President for a third term.
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A topless protester shouts at Putin and German Chancellor Angela Merkel during a visit to the Hanover Industrial Fair in central Germany in April 2013. Human rights groups say civil liberties and democratic freedoms have suffered during Putin's rule.
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Putin addresses the media during his visit to Hanover.
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Putin and his wife, Lyudmila -- seen here in 2012 -- announced the end of their marriage in June 2013.
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Putin poses for a photo with Russian Olympic athletes in Sochi, Russia, in February 2014. Russia hosted the Winter Olympic Games and won the most medals.
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From left, International Olympic Committee President Thomas Bach, Putin and Medvedev look at their watches before the closing ceremony of the Winter Olympics in February 2014.
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Putin, center, and Defense Minister Sergei Shoigu, left, arrive to watch a March 2014 military exercise at the Kirillovsky firing ground in Russia's Leningrad region.
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Putin, left, controls the puck during an ice hockey game between Russian amateur players and ice hockey stars at a festival in Sochi in May 2014.
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Putin takes part in a wreath-laying ceremony at the Tomb of the Unknown Soldier outside Moscow's Kremlin Wall in June.
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Putin speaks with Obama in November, during the Asia-Pacific Economic Cooperation summit in Beijing.
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Putin puts a shawl on Peng Liyuan, wife of Chinese President Xi Jinping, as they arrive to watch a fireworks show in Beijing in November.
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Several world leaders gather in Minsk, Belarus, in February to negotiate a ceasefire to the fighting in Ukraine. Putin is second from left, next to Belarussian President Alexander Lukashenko on the far left. Ukrainian President Petro Poroshenko is on the far right. At center, German Chancellor Angela Merkel gestures in front of French President Francois Hollande. Fighting between Ukrainian troops and pro-Russian rebels in the country has left more than 6,000 people dead since mid-April, according to the United Nations.
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"The world looks different today than it did before he re-assumed the presidency" in 2012, Biden continued. "President Putin must understand as he has changed, so has our focus."
As the vice president spoke, thousands of Russian troops were assembling in the country's northwest for a military exercise, just as European militaries were beginning similar exercises in the Arctic.
Russia's move was met with disapproval by NATO, which said it was "concerned by the size, scale and frequency" of the military exercises.
Obama, sitting alongside NATO's secretary general in the Oval Office on Tuesday, said Russia had taken an "increasingly aggressive posture" in Europe.