A man wearing a face mask takes a walk near the U.S. Capitol building in Washington D.C., the United States, May 13, 2020. (Xinhua/Liu Jie)

Burr was reported to have dumped stocks worth up to 1.72 million U.S. dollars in 33 different transactions on Feb. 13, a week before the stock market declined sharply.

WASHINGTON, May 14  -- Republican Senator Richard Burr, who is under investigation for stock trades he had made ahead of a market downturn triggered by the coronavirus pandemic, is stepping aside as chairman of the U.S. Senate Intelligence Committee, Majority Leader Mitch McConnell announced on Thursday.

"Senator Burr contacted me this morning to inform me of his decision to step aside as Chairman of the Intelligence Committee during the pendency of the investigation," McConnell said in a statement. "We agreed that this decision would be in the best interests of the committee and will be effective at the end of the day tomorrow."

The FBI reportedly served Burr with a search warrant and seized a cell phone of his on Wednesday, as part of the Justice Department's investigation into his stock trades.

Burr was reported to have dumped stocks worth up to 1.72 million U.S. dollars in 33 different transactions on Feb. 13, a week before the stock market declined sharply.

He and other senators had received closed-door briefings from U.S. public health officials on the risk posed by the coronavirus, before most Americans were warned about the potential economic fallout of the pandemic.