NEW YORK (AP) — A battle is brewing between two of Fox News’ biggest stars after conservative host Sean Hannity accused colleague Megyn Kelly of backing Hillary Clinton.

The spat began Wednesday night on Kelly’s program, when the anchor criticized both GOP presidential nominee Donald Trump and the Democratic candidate, Clinton, for avoiding tough media interviews. She said Trump “will go on Hannity and pretty much only Hannity and will not venture out to the unsafe spaces these days.”

Hannity responded on Twitter, writing “u should be mad at @HillaryClinton Clearly you support her. And @realDonaldTrump did talk to u.” When another Twitter user told Hannity he should stand by his colleagues, the host said, “Sure. When they stand by me.”

Hannity is a vocal supporter of Trump and has acknowledged giving him campaign advice.