Secretary of State nominee Mike Pompeo told senators at his confirmation hearing Thursday he has been questioned by special counsel Robert S. Mueller III in his investigation into connections between the Trump campaign and Russian operatives.

Specifically, Mueller questioned the current CIA chief on a West Wing conversation last March with President Donald Trump and Director of National Intelligence Dan Coats in which the president reportedly asked Coats to get then-FBI head James B. Comey to drop his investigation into  former national security adviser Michael Flynn.

Under hard questioning from Robert Menendez of New Jersey, the top Democrat on the Foreign Relations Committee, Pompeo repeatedly refused to discuss the conversation during the public hearing.

“Senator, I don’t recall what [Trump] asked me that day, precisely,” Pompeo said, adding that the president “has never asked me to do anything that I considered remotely improper.”

Menendez said he did not believe Mueller would object to him speaking and called the nominee’s reticence “troubling.”

Other Democrats tried unsuccessfully to get Pompeo to publicly give his opinion about elements of the special counsel investigation, which the president has repeatedly castigated as a “witch hunt.”

“I came here today to talk about my qualifications to be the secretary of State,” Pompeo said. “I am not going to weigh into the active investigations that are going on.”

Pompeo, who graduated magna cum laude from Harvard Law School, said he was “in no position to make a comment” on the legal question of whether Trump has the authority to fire Mueller.

Watch: Lawmakers Press Pompeo On Syria Response Without Congressional Approval

North Korea

With talks expected this spring between Trump and North Korean leader Kim Jong Un, Pompeo said he was confident the administration can avoid falling into the same trap as its predecessors in negotiating with Pyongyang.

During previous rounds of nuclear negotiations with the Clinton and George W. Bush administrations, the United States provided foreign aid to North Korea in exchange for nuclear dismantlement steps that North Korea subsequently reversed.

“President Trump isn’t one to play games at the negotiating table — and I won’t be either,” Pompeo said.

The former congressman from Wichita, Kansas, denied he had ever advocated regime change in North Korea.

Menendez’s office then quickly circulated to the press comments Pompeo made to a Washington audience last fall, where he said: “If Kim Jong Un should vanish, given the history of the CIA, I’m just not going to talk about it.”

During the hearing, Pompeo acknowledged the “enormous diplomatic work” involved in getting a successful resolution to the North Korea nuclear crisis but left the window open for a U.S. military strike.

He said he could “imagine times when America would need to take a response that would move past diplomacy” and launch an offensive attack on North Korea.

Massachussets Democrat Edward J. Markey then pushed back strongly, arguing that “the consequences of the United States initiating an attack on North Korea would be catastrophic, if we have not been attacked.”

Iran

Pompeo, whom Trump nominated last month to replace Rex Tillerson, pushed for a speedy confirmation vote.

He argued he needs to be in place to negotiate with European partners this month on potential changes or additions to the 2015 Iran nuclear deal before Trump decides in mid-May whether to continue certifying that Iran is in compliance with the agreement. If Trump abandons the certification, then economic sanctions on Iran resume, and that would probably upend the multinational nuclear accord.

“If confirmed, it will be an immediate personal priority to work with those partners to see if such a fix is achievable,” Pompeo said of European partners plus Russia and China who also signed the Iran deal. “If confirmed in time, I look forward to engaging key allies on this crucial and time-sensitive topic at the G-7 ministerial meeting on April 22 and the NATO ministerial meeting later that week.”

Pompeo told Maryland Democrat Benjamin L. Cardin that he was not prepared to say what advice he would give Trump next month if negotiations with Europe have not produced a path forward for improving the Iran deal without pulling out of it.

“It’s not a ‘yes’ or ‘no’ question,” he said. “It’s a hypothetical. We’re not at that point.”

The former member of the House Select Benghazi Committee subsequently said that if the United States reimposes sanctions and withdraws from the Iran agreement, he would not favor military strikes on Tehran if it resumes nuclear work the deal presently prohibits.

Rather, Pompeo said he would to try to achieve through diplomacy some sort of repeat of the international sanctions coalition put together by the Obama administration in order to pressure Tehran to enter into fresh nuclear negotiations with the goal of getting a stronger accord than the 2015 one.

Confirmation concerns

Despite the security challenges facing the United States, it is not at all clear Pompeo will receive the Foreign Relations panel’s support. Republicans hold just one more seat on the committee than Democrats and one GOP member, Rand Paul, has already announced he will vote against the CIA director.

Committee chairman Bob Corker suggested he had concerns about Pompeo’s close relationship with Trump even as he recognized the advantages that come with having the trust and respect of the president, which Tillerson lacked.

“I think it’s fair for our members to ask whether your relationship is rooted in a candid, healthy, give-and-take dynamic or whether it’s based on deferential willingness to go along to get along,” said the Tennessee Republican, who has famously feuded with Trump.

Menendez also had stern words for Pompeo.

“Many countries in the world already think the State Department is an extension of the CIA, so how you conduct yourself moving forward will be critical to our diplomacy,” the New Jersey Democrat said. “Will you advocate for robust diplomacy or will you take America into unnecessary and costly wars? Will you stand up to President Trump and say, ‘No, you are wrong in that view’? Or will you be a ‘yes’ man?”

Pompeo promised to make it his “first priority” to empower diplomats and issue experts at the State Department where morale plummeted during Tillerson’s one-year tenure. And he pledged to pick up the phone “on the first ring” when lawmakers call.

Pompeo’s nomination has been harshly condemned by liberal organizations, who point to, among other things, his past public comments criticizing Muslims as a group and his past work with some of the country’s biggest anti-Islam commentators and explicitly anti-Muslim groups. He has also been criticized for his past opposition to gay rights.

New Jersey Democrat Cory Booker referenced those concerns when he said: “I do not necessarily concur that you are putting forward the values of our nation when you believe there are people in our country who are perverse.”

Pompeo defended himself strongly, saying his “record is exquisite” when it comes to fair treatment of the men and women under his charge as a government official, military officer, and private businessman.

“I’ve worked closely with Muslim leaders and Muslim countries. The CIA has saved countless Muslim lives in my 15 months. This is the core of who I am,” he said.