Michael Flynn
Michael Flynn Reuters

President Donald Trump’s National Security Adviser Michael Flynn has resigned, the White House said late Monday, according to The Hill.

Gen. Keith Kellogg will be acting National Security Adviser, the statement said.

Flynn's future at the White House had been the topic of discussion all day, after reports emerged that he had talked about American sanctions against Russia with the country's ambassador before Trump was sworn in.

The reports contradicted his earlier comments that he never discussed the topic with Russian Ambassador Sergey Kislyak during a series of phone calls the month before Trump took office.

Vice President Mike Pence stood up for Flynn in January and told CBS that Flynn never spoke about sanctions with Kislyak during his calls to Russia.

The New York Times reported on Monday that Pence had been angry that he defended Flynn and embarrassed by the information Flynn withheld from him.

Hours before Flynn resigned, White House press secretary Sean Spicer told reporters that Trump was conferring with Pence on the matter.

The resignation comes even after the FBI last month cleared Flynn of any wrongdoing following an investigation into his phone calls with the Russian envoy.

The FBI intercepted Flynn’s calls in December, as part of a larger investigation into alleged interference in the U.S. presidential election by the Russian government.

However, the FBI probe found no evidence of wrongdoing or that Flynn had any illicit ties to Russian officials, the reports at the time claimed.