U.S. President Donald Trump says former national security advisor Michael Flynn's lies to the FBI destroyed his life while nothing happened to his Democratic opponent, Hillary Clinton who, he claims, also lied.

Former U.S. National Security Adviser Michael Flynn pleaded guilty on Friday to lying to the FBI, in an escalation of an investigation into alleged ties to Russia that has cast a cloud over President Donald Trump's administration.

U.S. President Donald Trump didn't respond to questions shouted at him by reporters about the indictment of his former National Security Adviser Michael Flynn.

Former U.S. National Security Adviser Michael Flynn pleaded guilty on Friday to lying to the FBI, in an escalation of an investigation into alleged ties to Russia that has cast a cloud over President Donald Trump's administration.

Former U.S. national security adviser Michael Flynn arrived in court on Friday morning to face charges that he lied to the FBI.

Investigators working for U.S. special counsel Robert Mueller, who is investigating whether President Donald Trump's 2016 campaign colluded with Russia, have asked the White House for documents related to his former national security adviser Michael Flynn, the New York Times is reporting.

Former FBI director James Comey accused U.S. President Donald Trump on Wednesday of asking him to drop an investigation of former national security adviser Michael Flynn as part of a probe into Russia's alleged meddling in the 2016 presidential election.

A former senior U.S. law enforcement figure said on Monday she warned President Donald Trump's White House in January about then-national security adviser Michael Flynn because she feared he could have been open to blackmail by Russia.

The White House says President Trump did not know until this week that his former national security adviser, Michael Flynn, had been working as a representative for Turkey.

President Donald Trump asked his national security adviser to resign after White House lawyers reviewed a warning from the Justice Department that Michael Flynn had misled officials about his conversations with a Russian envoy.

The resignation of U.S. President Donald Trump's national security adviser, Michael Flynn, is an internal matter for the United States, Kremlin spokesman Dmitry Peskov says.

Michael Flynn has resigned as US President Donald Trump's national security adviser over his contacts with Russia.