WASHINGTON — At least one Democratic political strategist has gotten a blunt warning from the White House to never appear on Fox News Channel, an outlet that presidential aides have depicted as not so much a news-gathering operation as a political opponent bent on damaging the Obama administration.

The Democratic strategist, who spoke on condition of anonymity so as not to run afoul of the White House, said that shortly after an appearance on Fox, he got a phone call from a White House official telling him not to be a guest on the show again. The call had an intimidating tone, he said.

The message was, "We better not see you on again," said the strategist. An implicit suggestion, he said, was that "clients might stop using you if you continue."

White House communications director Anita Dunn said that she had checked with colleagues who "deal with TV issues" and they had not told people to avoid Fox. On the contrary, they had urged people to appear on the network, Dunn wrote in an e-mail.

But Patrick Caddell, a Fox News contributor and a former pollster for Democratic President Jimmy Carter, said he had spoken to Democratic consultants who said they were told by the White House to avoid appearances on Fox. He declined to give their names.

Last month, Dunn told CNN that Fox was, in effect, an "arm" of the Republican Party. "Let's not pretend they're a news network the way CNN is," she said.