A slew of Democrats on Wednesday tweeted “Happy Holidays” to the Republican National Committee and the National Republican Congressional Committee (NRCC).

The Democratic National Committee (DNC) encouraged supporters to tweet the phrase following controversy over products the NRCC has been selling that made light of people using the phrase "Happy Holidays."

Some items sold by the NRCC said only liberals would use such the phrase.

Democrats have criticized that suggestion as offensive.

“It isn't just divisive. It's offensive,” said DNC Communications Director Mo Elleithee.

“The official organization charged with electing Republicans to the House — the national Republican Party! — thinks that telling people "Happy Holidays" is something that only liberals do,” he wrote in a morning email to Democratic supporters.

His email links to a webpage on the DNC’s site that prompts people to wish Republicans “Happy Holidays” by selecting Christmas, Hanukkah, Kwanzaa, New Years, Festivus or holidays. It then generates a tweet based on the holiday selected, and includes the hashtag: #HappyHolidaysGOP.

More than 1,000 people tweeted it on Wednesday, according to social media analytics tool TOPSY.

The NRCC launched a mug this week in its online store that says, “ ‘Happy Holidays’ is what liberals say.”

A shirt with the same phrase sold out last week and is no longer being sold.

Since last week, the committee has also been selling a shirt that says, “I’m not afraid to say ‘Merry Christmas,’ ” which is available in red or green.