Family Research Council President Tony Perkins announced Tuesday that he was endorsing Texas Sen. Ted Cruz for president.

Perkins made the announcement on Fox News' "The Kelly File", then followed up his endorsement with a series of explanatory tweets.

Perkins said he supported Cruz when he ran for the Senate in 2012 and says he's confident the Texan governs "based on conservative principles."

Cruz is in a tight race with Donald Trump to win the GOP vote in the first-in-the-nation presidential caucuses in Iowa on Monday.

The Associated Press contributed to this report.