Updated

Republican Rep. Steve Stockman on Tuesday pressed President Obama and his de facto campaign arm, Organizing for Action, for more information on White House gun-control efforts, amid new allegations that Obama supporters are flooding congressional Twitter accounts with "phony" and "fraudulent" anti-gun messages.

The Texas congressman said he sent letters to both the White House and OFA after learning Monday that he and 15 other Capitol Hill lawmakers had received computer-generated tweets that included the #WeDemandAVote hashtag -- which Obama encouraged supporters to use.

"I am deeply troubled by this week's revelation supporters of President Obama's anti-gun campaign employed 'spambots' to send fake Twitter messages to members of Congress intending to create the false appearance of grassroots support," he wrote.

Two other Republican lawmakers -- Michael Grimm of New York, and Adam Kinzinger of Illinois -- also appeared to receive similar messages that may be linked to former Obama digital strategist Brad Schenck.

Stockman indicated he wants to know whether any Obama staffers knew about the tactic, which he described as an effort to "defraud members of Congress." He asked for any reports, audits, letters, expense logs and other records relating to the president's gun-control campaign .

Bloggers first spotted the "spambot" trend and said they suspected something fishy because the senders had sent no other tweets, had no followers and followed nobody.

“Obama’s anti-gun campaign is a fraud,” Stockman said Monday.

The White House did not respond to a request for comment.

A review of Stockman’s Twitter account by staffers and conservative bloggers showed at least 16 identical tweets.

Of the 16 members of Congress who have received the tweets, nine are Democrats and seven are Republicans.