Donald Trump's running mate Mike Pence is breaking with the Republican nominee by endorsing House Speaker Paul Ryan in his primary fight.

Pence said in a phone interview with Fox News Channel that he's pleased to endorse Ryan.

The move comes a day after Trump said in an interview that he's "just not quite there yet" when it comes to backing Ryan, who has at times been critical of Trump's most controversial comments.

Pence says that he spoke with Trump Wednesday morning about his "support for Paul Ryan and our longtime friendship."

He says Trump, "strongly encouraged me to endorse Paul Ryan in next Tuesday's primary. And I'm pleased to do it."