Former national security adviser Michael Flynn texted supportive messages to Rep. Matt Gaetz, a Florida Republican and top ally of President Trump.

The messages came months after Flynn started cooperating with special counsel Robert Mueller's investigation.

According to multiple reports, Flynn texted Gaetz: "You stay on top of what you're doing. Your leadership is so vital for our country now. Keep the pressure on." He later texted images of a bald eagle and an American flag to Gaetz after William Barr was confirmed as attorney general.

Gaetz, a heavy critic of the Mueller investigation, said he had no previous relationship with Flynn and did not respond to the messages.

Flynn had been cooperating with Mueller's special counsel after pleading guilty to making false statements to the FBI about contacts with Russia's ambassador by the time he texted Gaetz.

Trump tweeted on Friday he was not warned about Flynn's behavior before appointing him national security adviser, though then-President Barack Obama reportedly advised Trump against hiring Flynn in 2016. Flynn was in the position for less than a month.