Washington (CNN) -- The future of the Korean peninsula relies on U.S. involvement in the peace process, South Korean President Park Geun-hye told a joint meeting of Congress Wednesday.
Park said that despite recent tensions with communist North Korea, reunification of the Koreas is possible, even if it "feels distant today."
"North Korea continues to issue threats and provocations, firing long range missiles, staging nuclear tests and undermining peace on the peninsula and far beyond it," Park said. "The Korean government is reacting resolutely but calmly. We maintain the highest level of readiness."
And as long as the United States and South Korea maintain their strong relationship, Park said, "You may rest assured, no North Koreans provocation can succeed."
Throughout much of late March and April, North Korea ratcheted tensions with the United States and South Korea by issuing a cadre of bellicose statements on nuclear war with the South. Recently, however, tensions have begun to wane, signaled by the fact that, according to a U.S. official, North Korea has withdrawn two mobile ballistic missiles from a launch site in the eastern part of the country.
Initially, U.S. defense officials told CNN that the missiles' movements to the area signaled North Korean Leader Kim Jong Un was planning to test launch missiles. In response, the United States and Japan stepped up missile defenses in the region.
Park said moves like this did nothing for the peace process.
"I am confident that trust is the path to peace, the path to a Korea that is whole again," she said. "The Republic of Korea will never accept a nuclear armed North Korea. Pyongyang's provocations will be met decisively."
The North has long used missile tests and its nuclear arsenal as a way to extract concessions and rewards from the international community. Park said this strategy is part of the North's "incompatible" aim to pursue "two goals at once."
"You cannot have your cake and eat it too," Park said.
Her speech to Congress comes just a day after she met with President Barack Obama at the White House. Obama, in a news conference after the meeting, said that North Korea's recent provocations have only made the United States and South Korea closer.
"If Pyongyang thought its recent threats would drive a wedge between South Korea and the United States or somehow garner the North international respect, today is further evidence that North Korea has failed again," Obama said. "The United States and the Republic of Korea are as united as ever ... North Korea is more isolated than ever."
Park, South Korea's first female president, took office in February, shortly before North Korea conducted its most recent nuclear test and has since taken a tough stance on perceived aggression from the North.
In an interview with CBS Monday, Park said even a small attack would warrant a military response.
"Yes, we will make them pay," she said.
In her remarks Wednesday, Park also singled out the four current members of Congress who served during the Korean War -- Rep. John Conyers, Rep. Charles Rangel, Rep. Sam Johnson and Rep. Howard Coble. Each congressman stood as Park acknowledged them and received loud applause for their service.
"Gentleman, my country thanks you," she said.
Park said as part of her visit, she traveled to the Korean War Memorial on the National Mall in Washington. Citing an inscription at the monument -- "Our nation honors our sons and daughters who answered the call to defend a country they never knew and a people they never met" -- Park reflected on what those words meant to the country she now leads.
"Time and again, I am moved when I read those familiar words," she said. "Our profound gratitude to America's veterans, their blood, sweat and tears helped safeguard freedom and democracy."
CNN's Gabriella Schwarz and Barbara Starr contributed to this report.