In a speech in Washington, D.C., on Friday, outgoing Lt. Gov. David Dewhurst doubled down on claims that Muslim prayer rugs had been found on the Texas-Mexico border.

"Prayer rugs have recently been found on the Texas side of the border in the brush," Dewhurst said at the Values Voter Summit, according to a report on Friday by Talking Points Memo, a liberal news site.

Dewhurst, who has served in his position since 2002 but lost his bid for re-election to state Sen. Dan Patrick, R-Houston, in the GOP primary, made similar assertions last week during The Texas Tribune Festival. He said during a panel discussion on border security that a note reading “See you in New York” was found on the border, suggesting that Islamic extremists might have left it behind while entering Texas.

But a Texas congressman who sits on the U.S. House Homeland Security Committee has argued that there's no threat of extremism on the border. U.S. Rep. Beto O’Rourke, D-El Paso, said during that same panel that top Pentagon officials had denied that there was any threat on the Texas-Mexico border from the Islamic State (ISIS) or similar groups. He added that similar claims were made about extremists crossing into Texas from Mexico during the United States’ conflicts with Libya in the 1980s, which he also mentioned to The Economist in an article published this week.

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“This tale is spread by internet conspiracy-mongers and politicians big enough to know better,” O'Rourke told the publication.

Calls to Customs and Border Protection seeking comment on the veracity of the prayer rug reports were not immediately returned.

Dewhurst’s comments echo what Gov. Rick Perry hinted at last month when he said there was a “real possibility” extremists affiliated with ISIS could cross into the U.S. through Mexico. The statements sparked outrage from the Mexican government, which called the claims ridiculous.

Also on Saturday's panel, Texas Agriculture Commissioner Todd Staples said that according to law enforcement, several Ukrainians have been detained on the state's southern border. The country has been embroiled in a months-long conflict between Russian-backed rebels and Ukranian loyalists, causing heightened tension between Russia and the U.S. and its allies. 

U.S. Rep. Henry Cuellar, D-Laredo, said the U.S. must remain vigilant, but he agreed that the talk about extremists crossing the border is nothing new. Almost 10 years ago, Rick Flores and Sigifredo Gonzalez, respectively the former sheriffs of Webb and Zapata counties, sounded alarm bells over the possibility of members of al-Qaida and other groups crossing into South Texas from Mexico.

“I don't think we've been taken serious along the border of Mexico, and I think it's time that they reevaluate the potential for — the potential threat for terrorism in this area and how they make their way through,” Flores told CNN in 2005, according to a transcript of the interview.