WASHINGTON – President Donald Trump is always attacking the news media, but over the weekend he struck an unusual target: Fox News.

While he has described Fox as his favorite news outlet, Trump went after them late Sunday in a series of tweets. He criticized news anchors he didn't name as well as the network's hiring of Democratic consultant Donna Brazile as a political commentator.

"@FoxNews is changing fast, but they forgot the people who got them there!" Trump said in one tweet.

The reason for the outburst is unknown.

Trump has often mocked Brazile after WikiLeaks produced evidence that she shared information about CNN debates and town halls with Hillary Clinton's presidential campaign.

In March, Brazile wrote that her decision to commentate for Fox is “rooted in the belief that you cannot make progress, let alone reach compromise, without first listening to, and understanding those who disagree with you on critical issues.”

Trump has often praised Fox commentators like talk show host Sean Hannity, but he has on occasion criticized its news gathering organization on items ranging from polls to its sponsorship of town halls with Democratic presidential candidates.

On June 17, Trump tweeted: "Something weird going on at Fox."