National Security Advisor Michael Flynn has resigned, the White House announced in a statement late Monday.
President Donald Trump has named Retired Army Lt. Gen. Joseph Keith Kellogg, Jr. as acting national security advisor.
The move comes after Flynn was unable to shake growing calls for his resignation, following reports that he had misled Vice President Mike Pence on discussions he had with a Russian official before Trump took office.
Flynn had originally told Pence that he did not discuss the issue of sanctions with Russian Ambassador Sergey Kislyak in a series of phone calls the month before President Trump was sworn in.
Pence then told CBS in January that Flynn had never spoken about the sanctions during his calls to Russia.
However, after anonymous U.S. officials leaked a transcript of a call between Flynn and Kislyak showing that the topic was discussed, Flynn said the topic may have come up, but he had forgotten.