UPDATE 11:09 a.m.:
Michael Flynn Jr., the son of recently resigned national security advisor Michael Flynn Sr., tweeted that the "disinformation campaign against my father won" Tuesday morning before deleting his tweet, The Hill reported.
Flynn Jr. then drew criticism from Hillary Clinton and others for his role in the "Pizzagate" conspiracy theory. His promotion of the conspiracy ultimately got him removed from Trump's transition team.
UPDATE 10:30 a.m.:
House Speaker Paul Ryan (R-WI), speaking at a GOP leadership conference, said President Trump made the right decision to ask for the resignation of former national security advisor Michael Flynn. However, it is not believed that Flynn was asked to resign by Trump, CNN reported.
"I'm not going to pre-judge ... until we have all of the information," Ryan said.
Ryan also defended Trump's discussion of foreign policy at Mar-a-Lago.
UPDATE: 7:20 a.m.:
The Trump administration is working quickly to name a permanent replacement after National Security Adviser Michael Flynn resigned Monday night.
Retired Lt. Gen. Joseph Keith Kellogg was named acting national security adviser and he is considered a top candidate. Former CIA director David Petraeus and retired Navy SEAL Robert Harward are also reportedly on the short list. This position does not requite Senate confirmation.
National security adviser Michael Flynn has resigned after reports that he misled Trump administration officials about his contacts with Russia's ambassador to the U.S.
Flynn's departure less than one month into the Trump administration marks an extraordinarily early shakeup in the president's senior team of advisers. Flynn was a loyal Trump supporter throughout the campaign, but his ties to Russia caused concern among other senior aides.
Flynn initially told Trump advisers that he did not discuss sanctions with the Russian envoy during the transition. Vice President Mike Pence, apparently relying on information from Flynn, publicly vouched for the national security adviser.
Flynn later told White House officials that he may have discussed sanctions with the ambassador.
President Trump has selected Lt. General Joseph Keith Kellogg, Jr. as acting national security adviser following Michael Flynn's resignation.
This is a developing story.
The Associated Press contributed to this report.