U.S. President Donald Trump leaves the White House for the World Economic Forum in Davos Switzerland, in Washington D.C., the United States, on Jan. 24, 2018. (Xinhua/Ting Shen)

WASHINGTON, Jan. 24 (Xinhua) -- U.S. President Donald Trump said Wednesday that he is willing to talk to special counsel Robert Mueller as part of the ongoing Russia probe that appears to have inched closer to the president's inner circle.

LOOKING FORWARD TO IT

"I'm looking forward to it," Trump told reporters at the White House when asked if he was going to talk to Mueller. "I would do it under oath," he said.

Mueller is investigating allegations of Russian interference in the 2016 U.S. presidential election and possible collusion between the Trump campaign and Moscow.

The special counsel's team was also reportedly looking into any attempts by Trump to obstruct the investigation.

"There has been no collusion whatsoever," Trump said as he repeatedly did, adding "there's no obstruction whatsoever."

U.S. President Donald Trump shakes hands with Russia's President Vladimir Putin during their bilateral meeting at the G20 summit in Hamburg, Germany July 7, 2017.(Xinhua/REUTERS)

Trump has repeatedly denied allegations of collusion between his campaign and Russia while describing the Russia probe as a "hoax" or a "witch hunt."

"You fight back," he said Wednesday, and such a response is characterized as "obstruction."

A participant dressed as both Russia's President Vladimir Putin and U.S. President Donald Trump attends a protest against Trump's announcement that he plans to reinstate a ban on transgender individuals from serving in any capacity in the U.S. military, in Times Square, in New York City, New York, U.S., July 26, 2017. (Xinhua/REUTERS)

The president also said that he expects to speak with Mueller in two to three weeks, adding that whether he would show up was subject to his lawyers' advice, while he would personally like to do it.

HEATING UP

Since his appointment following Trump's firing of James Comey, former director of Federal Bureau of Investigation (FBI), Mueller has investigated four former members of Trump's campaign team, two of whom had pleaded guilty, a sign that the investigation is getting closer to Trump's inner circle.

A day before Trump's remarks, the Justice Department confirmed that Attorney General Jeff Sessions was interviewed for several hours last week by the special counsel's office.

U.S. Attorney General Jeff Sessions speaks at a news conference at the U.S. Justice Department in Washington D.C., United States, on Nov. 29, 2017. (Xinhua/Ting Shen)

The Sessions-Mueller interview was the first time that investigators for Mueller were known to have interviewed a member of Trump's cabinet.

Sessions, an early supporter of Trump's presidential bid, has drawn attention for his contacts with Russia during the presidential campaign and his role in Trump's firing of Comey.

In response, Trump said Tuesday that he had not talked to Sessions about what he discussed with Mueller's investigation, stressing that he is not concerned about the meeting at all.

Comey was also reportedly questioned by the special counsel.

The Washington Post reported Tuesday that Mueller specifically wants to question Trump in the next several weeks concerning his decisions to oust Comey and national security adviser Michael Flynn.

Flynn has pleaded guilty to lying to the FBI about his contacts with former Russian ambassador to the United States, and was cooperating with Mueller's investigation.

Comey has publicly said that Trump asked him to drop a case into Flynn.

A group of protesters are stopped by secret service officers as they try to deliver a made up one way plane ticket to Russia for U.S. President Donald Trump and his family members at the Trump Tower during a demonstration to mark his birthday, in New York on June 14, 2017. (Xinhua/AFP)

Donald Trump Jr., together with Jared Kushner, son-in-law of Trump and a senior White House adviser, and former Trump campaign manager Paul Manafort, had been repeatedly linked for attending a meeting with a Russian lawyer in the hope of getting hands on previously-promised "damaging information" about Trump's then-opponent, Democratic presidential candidate Clinton.

The meeting, which took place on June 9, 2016 at Trump Tower in New York, also involved a Russian-born American lobbyist, a senior executive of a Russian real estate developer, an interpreter, and a British music publicist who proposed and later arranged the meeting via emails with Trump Jr.