U.S. Secretary of State Mike Pompeo participated in three hours of sometimes adversarial questioning on Wednesday during testimony to the Senate's foreign relations committee.
The majority of the questions focused on President Donald Trump's recent summits with Russian President Vladimir Putin and North Korean leader Kim Jong-un.
During his opening statement, Pompeo said the U.S. is engaged with "patient diplomacy" with North Korea but won't let negotiations "drag out to no end."
He also said the Trump administration's goals on North Korea are unchanged and the "objective remains the final, fully verified denuclearization of North Korea as agreed to by Chairman Kim Jong-un."
Pompeo dodged questions about specifics on how North Korea defines "complete denuclearization" but said he "will concede there is an awful long way to go" following a summit between Trump and Kim.
When asked to detail verifiable evidence of progress toward denuclearization, Pompeo stated, "We are sitting at the table having conversations."
Pompeo also pointed to a report this week from an American research group that the North has begun dismantling its main missile-engine test site. The report was based on an analysis of satellite imagery by the website 38 North.
Following the Singapore summit, Trump declared Pyongyang was already returning long-sought remains of Americans killed during the Korean War, which was not accurate. He later modified his comments, saying North Korea had "already sent back or are in the process of sending back" remains. On Wednesday, Pompeo said the remains would be returned "in relatively short order."
After Pompeo's most recent trip to North Korea, Kim accused the envoy of making "gangster-like" demands.
Tough talk on Crimea
Before the hearing started, the administration tried to get ahead of questions about Trump's relationship with Russia by postponing a second proposed summit with Putin and issuing a statement declaring that the U.S. will never recognize the annexation of Crimea.
Pompeo issued a statement titled the "Crimea Declaration" that said the U.S. will continue to insist that Ukraine's territorial integrity be restored. He said the U.S. would hold to its long-standing principle of refusing to recognize Kremlin claims of sovereignty over territory seized by force in violation of international law. And he called for Russia to respect principles it claims to respect and "end its occupation of Crimea."
"In concert with allies, partners, and the international community, the United States rejects Russia's attempted annexation of Crimea and pledges to maintain this policy until Ukraine's territorial integrity is restored," Pompeo said in the declaration, which was released by the State Department shortly before he was to testify.
Even before it was released, Pompeo was taking a tough line on Russia and defending the Trump-Putin meeting as he prepared for his Senate testimony.
In an interview transcript released ahead of the Crimea statement, Pompeo said Trump and Putin "didn't find much place to agree" on Ukraine when they met in Finland last week. He said Trump made clear to Putin that the so-called Minsk Accords to settle the Ukraine conflict is the right path forward.
He also reiterated U.S. support for an investigation that held Russia responsible for downing a Malaysian airliner over east Ukraine in 2014. Pompeo said that what the Russians did was "deeply immoral" and that those responsible for the MH17 disaster should be held accountable.
Pompeo made the comments in a Tuesday interview with the Australian Broadcasting Corporation in California, where he and Defence Secretary James Mattis co-hosted meetings this week with their Australian counterparts.
In the interview, Pompeo acknowledged he was not in the room when Trump and Putin met for nearly two hours in Helsinki. But he said he had a "good understanding" of what took place based on his presence at a larger meeting between the two sides as well as conversations with Trump and Russian Foreign Minister Sergei Lavrov.
"It was an incredibly constructive engagement for President Trump and President Putin, an important one for the world," Pompeo said. "These are two nuclear superpowers. They ought to be engaged in conversations, and they covered a wide range of topics. They disagreed on many things but also set forward some constructive paths on important topics."
Earlier Wednesday, national security adviser John Bolton cited special counsel Robert Mueller's investigation into Russian interference in the 2016 election as the reason for delaying the second summit.
"The president believes that the next bilateral meeting with President Putin should take place after the Russia witch hunt is over, so we've agreed that it will be after the first of the year," Bolton said.
The White House said last week that Trump had directed Bolton to invite Putin to Washington for a meeting in the fall. This came amid the backlash over Trump's performance at a news conference with Putin following their Helsinki summit, and many members of Congress had objected to them meeting again in the fall.