Special counsel Robert Mueller raised the prospect of subpoenaing President Donald Trump in March to answer questions in his investigation into alleged Russian meddling in the 2016 election, The Washington Post reported Tuesday.

The Post, citing four people familiar with the encounter whom it didn't identify, said Mueller brought up trying to compel the president to testify before a grand jury in a meeting with Trump's lawyers in early March.

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The disclosure follows closely on the publication by The New York Times of almost four dozen questions it said Mueller wants to ask the president. They include questions about Trump's ties to Russia, his firing of James Comey as director of the FBI and whether he tried to interfere with Mueller's investigation.

NBC News hasn't independently verified the Times or Post reports.

Mueller discussed a subpoena in a meeting in early March, The Post reported — before John Dowd, the lead outside attorney advising Trump on the Russia investigation, stepped down. The Associated Press reported that Dowd confirmed The Post report.

Without referring to the reports, Trump tweeted on Wednesday morning that there was no "collusion" or obstruction of justice.

There was no Collusion (it is a Hoax) and there is no Obstruction of Justice (that is a setup & trap). What there is is Negotiations going on with North Korea over Nuclear War, Negotiations going on with China over Trade Deficits, Negotiations on NAFTA, and much more. Witch Hunt! — Donald J. Trump (@realDonaldTrump) May 2, 2018

A source familiar with the proceedings told NBC News on Tuesday night that the president's new legal team, led by former New York Mayor Rudolph Giuliani, is still getting up to speed and that no decisions have been made. A White House official familiar with the proceedings said nothing had been taken off the table.

NBC News reported last month that Trump's legal team had discussed making the case that a sitting president can't be force to comply with a subpoena, according to people familiar with the discussions. The argument hinges on the idea that a sitting president can't be indicted and if a president can't be indicted, he can't be forced to comply with a subpoena.

Trump's personal attorney, Jay Sekulow, said Tuesday night: "We do not discuss conversations we have or have not had with the Office of Special Counsel." Ty Cobb, a member of Trump's White House legal team, had no comment. The Post reported that a spokesman for Mueller declined to comment.