Notably, Franks neither confirmed nor denied that he was going to resign.
Franks told reporters he would release a statement explaining his decision to step down.
Franks told Roll Call that a statement would be forthcoming.
"There's been rumors swirling around him for years, at least in 2012", the Republican source told Roll Call. He's a staunch social conservative who sponsored House-passed legislation to make it a crime for any person to perform an abortion if the age of the fetus is 20 weeks or more.
Franks was seen huddling with fellow Republicans on the floor of the House Thursday, in what appeared to be a prayer circle.
Rep. Trent Franks (R-Ariz) (left) during a hearing on the District of Columbia Pain-Capable Unborn Child Protection Act at Rayburn House Office Building in Washington on May 23, 2013.
He supported President Donald Trump previous year, even in the wake of the "Access Hollywood" tape, by saying Trump's words, while bad, did not compare to Democratic presidential candidate Hillary Clinton's support of abortion rights.
Trent is now serving his eight term in Congress - he was first elected in 2002. Franks won an eighth term last fall by 37 points.
According to Arizona state law, the governor will have to call a special election to fill the seat as Franks' resignation would come more than 6 months before the next general election.