 -- President Donald Trump and Secretary of State Rex Tillerson met with Russian Foreign Minister Sergey Lavrov Wednesday morning to discuss a dizzying array of issues amid the firestorm over Trump’s abrupt firing of FBI Director James Comey.

Despite ongoing investigations into his campaign’s ties to Russia, including one that was being led by Comey, Trump "emphasized his desire to build a better relationship between the United States and Russia," according to a White House readout.

For his part, Lavrov dismissed allegations of Russian hacking of the presidential election and scorned reporters for asking about Comey.

“Was he fired?” Lavrov responded mockingly at the State Department. “You’re kidding! You’re kidding!”

“You all seem to be grownups. I never thought that I'd have to answer such questions particularly being in the U.S., taking into account your highly developed democratic political system," he added sarcastically at a press conference later in the day.

Lavrov also asserted that Trump agrees that Russia did not meddle in the election, and when asked if Trump told him that in their meeting, Lavrov said he didn't have to because Trump has said as much publicly.

“President Trump will publicly say that all of it is false news,” he said.

The foreign minister is the highest-ranking Russian official Trump has met with as president. The two met privately in the Oval Office - an honor reserved for distinguished guests - alongside Tillerson and Russian ambassador Sergei Kislyak. Kislyak himself is a controversial figure for his meetings with Trump transition officials, including former national security adviser Michael Flynn. The retired Lt. Gen. lied about his contacts with Kislyak, which eventually led to his dismissal.

Find more pictures of Sergey Lavrov's visit to Washington, DC on @MFA_Russia's Flickr account ??https://t.co/TKMEUwjbDp?? pic.twitter.com/zsJHbjBOh5

The White House also said that Trump "emphasized the need to work together to end the conflict in Syria, in particular, underscoring the need for Russia to rein in the Assad regime, Iran, and Iranian proxies," according to its statement.

Tillerson and Lavrov met one-on-one earlier in the day – the second time during Tillerson’s brief tenure in office after he traveled to Moscow in April. Today was Lavrov’s first trip to Washington since August 2013 — a sign of the high-stakes conversations between the two countries, even as Tillerson and others have previously said the relationship is at an all-time low.

While Lavrov held a press conference after their meeting, Tillerson declined to answer reporters’ questions. In a statement, State Department spokesperson Heather Nauert said the pair "discussed the importance of defeating ISIS, de-escalating the violence in Syria, and ensuring that humanitarian assistance reaches hundreds of thousands of civilians throughout the country."

Nauert added that Tillerson and Lavrov shared support for the UN-led effort to resolve the Syrian conflict.

It was a sign that the U.S. may be closer to working with Russia in Syria to implement the so-called “de-escalation zones” that Russia, Turkey, and Iran agreed to create. Lavrov went so far as to say the idea was originally Trump’s and that Russia was simply implementing his idea “in practical terms.”

The U.S. has been wary of Iran’s involvement in that agreement and of cease-fires in Syria in general, after a number of failed attempts.

But on the campaign trail, Trump often called for the creation of safe zones in Syria, to keep refugees from fleeing to the U.S. Tillerson mentioned "interim zones of stability" in an address to the Global Coalition to Counter ISIS but has offered few details publicly. Lavrov said he provided more concrete ideas during their meeting in Moscow.

Democrats on the House Foreign Affairs Committee tweeted a mocking “correction” of the State Department’s press release on today’s meetings.

The State Department said that Tillerson did discuss Ukraine, stressing “the need for progress toward full implementation of the Minsk agreements” and promising sanctions on Russia will remain in place until then.

The meeting between the two top diplomats was originally scheduled to take place on the sidelines of the Arctic Council ministerial summit in Fairbanks, Alaska. Lavrov and Tillerson are traveling there now separately, where they will be joined by the ministers of the council’s six other countries to discuss scientific and environmental issues.

ABC News’ Alexander Mallin contributed to this report.