Sen. Bob Corker admonished President Donald Trump on Sunday after the president lashed out at him on Twitter.

"It's a shame the White House has become an adult day care center. Someone obviously missed their shift this morning," wrote Corker, the Republican senator from Tennessee.

The tweet came an hour after Trump extensively criticized Corker, repeating claims that the senator sought Trump's endorsement before deciding against seeking reelection in 2018 — though Corker's own chief of staff said that the president offered to endorse the senator just last week.

Despite lobbying from top Republicans including Senate Majority Leader Mitch McConnell, Corker decided against running for reelection as polls indicated he may have been vulnerable to a Republican primary challenger.

Some on the right, like former White House chief strategist Steve Bannon, were considering backing a primary opponent.

Sunday's clash online was just the latest public spat in a relationship that has deteriorated significantly since Trump flirted with tapping Corker to be his 2016 running mate and nominating Corker to a cabinet position.

In May, the chairman of the Senate Foreign Relations Committee said the White House was in a "downward spiral" following reports that Trump had revealed highly sensitive intelligence to Russian officials.

In August, Corker criticized President Donald Trump's comments about white-nationalist protesters in Charlottesville, Virginia, saying Trump "has not demonstrated he understands the character of this nation."

And earlier this week, he criticized Trump for undermining Secretary of State Rex Tillerson's efforts to establish diplomatic channels with North Korea amid heightening nuclear tensions. Corker said Tillerson, Defense Secretary James Mattis, and White House chief of staff John Kelly are "those people that help separate our country from chaos."