Washington (CNN) -- President Barack Obama on Thursday signed into law new U.S. sanctions on Iran that he called another step in demonstrating that "the United States and the international community are determined to prevent Iran from acquiring nuclear weapons."
At a White House signing ceremony, Obama noted that the U.N. Security Council has passed the strongest sanctions to date against Iran, and that Australia, the European Union and Canada also have taken or are considering stronger steps to further isolate Iran's nuclear program and supporting entities.
"Consistent with the Security Council mandate, this legislation strengthens existing sanctions, authorizes new ones and supports our multilateral diplomatic strategy to address Iran's nuclear programs," Obama said of the new sanctions recently passed by Congress, which he called the toughest ever by the United States.
"It makes it harder for the Iranian government to purchase refined petroleum and the goods, services and materials to modernize Iran's oil and natural gas sector," Obama said. "It makes it harder for the Revolutionary Guards and banks that support Iran's nuclear programs and terrorism to engage in international finance. It says to companies seeking procurement contracts with the United States government -- if you want to do business with us, you first have to certify that you're not doing prohibited business with Iran."
The sanctions and other steps "are striking at the heart of the Iranian government's ability to fund and develop its nuclear programs," the president said.
"We are showing the Iranian government that its actions have consequences," Obama said. "And if it persists, the pressure will continue to mount, and its isolation will continue to deepen."
Last week, the U.S. Senate and House of Representatives approved the sanctions aimed at discouraging Iran's development of nuclear weapons. The sanctions target companies that sell refined petroleum products to Iran and international banks that do business with Iran's Islamic Revolutionary Guard.
Obama said the sanctions are targeted at Iranian elements tied to the nuclear program, rather than the Iranian people.
"This legislation imposes sanctions on individuals who commit serious human rights abuses," Obama said. "And it exempts from our trade embargo technologies that allow the Iranian people to access information and communicate freely. In Iran and around the world, the United States of America will continue to stand with those who seek justice and progress and the human rights and dignity of all people."
Iran says its nuclear energy program is intended for peaceful purposes. Obama, however, noted that Iran is the only signatory of the Nuclear Non-Proliferation Treaty that has "been unable to convince the International Atomic Energy Agency that its nuclear program is for peaceful purposes."
"For years, the Iranian government has violated its commitments, defied United Nations Security Council resolutions and forged ahead with its nuclear program -- all while supporting terrorist groups and suppressing the aspirations of the Iranian people," Obama said.
"This is not a day that we sought -- but it is an outcome that was chosen by the Iranian government when it repeatedly failed to meet its responsibilities," the president said. "The government of Iran still has a choice. The door to diplomacy remains open. Iran can prove that its intentions are peaceful."