The threat of a toothpaste bomb targeting flights destined for the Winter Olympics in Russia is “very specific and credible,” the chairman of the House Homeland Security Committee said Wednesday.

The Department of Homeland Security is warning some flights to Russia to look out for toothpaste and cosmetic tubes that could contain material to construct a bomb.

Rep. Michael McCaulMichael Thomas McCaulGOP chair urges Senate to pass DHS cyber reorganization bill GOP lawmaker's home listed as top single-family water user in Austin last year: report Hillicon Valley: EU hits Google with record B fine | Trump tries to clarify Russia remarks | Sinclair changing deal to win over FCC | Election security bill gets traction | Robocall firm exposed voter data MORE (R-Texas) said the threat is serious and that Homeland Security officials are tightening airport screenings as a precaution.

The United States is unlikely to further restrict the small amounts of liquid travelers can carry on board a plane in the U.S., however, since warnings have specifically been made on flights going from Europe to Russia.

“With respect to the three ounce, I don't think you're going to see that in the United States, but I know these flights that are emanating out of Russia, you'll probably see a tightening up of those screening procedures with any liquid gels, cosmetics and toothpaste,” McCaul said. 

A DHS official released a statement Wednesday saying it is not aware of a "specific threat to the homeland" at this time. The DHS regularly shares information with domestic and international partners.

The official added: "While we are not aware of a specific threat to the homeland at this time, this routine communication is an important part of our commitment to making sure we meet that priority. As always, our security apparatus includes a number of measures, both seen and unseen, and DHS will continue to adjust security measures to fit an ever evolving threat environment."

McCaul said a warning went out to airlines at 2 p.m. Wednesday to be on the lookout for material that could either be detonated on the plane or smuggled into the Olympics Village in Sochi, Russia. 

McCaul mentioned another threat from Chechen rebels who have trained in Syria.

“There is a concern that with that kind of training and trade craft that they can travel from Syria into the Sochi area,” he said. “That is of grave concern.”