One day after terrorists released a video promising to target the Winter Olympics in Sochi, Russia, next month, authorities are searching for a woman known as a black widow.
The term is given to widows of terrorists who vow to carry out an attack to avenge their husbands' death.
Authorities believe the widow, who hails from North Caucasus region -- a place known to be a hotbed for terrorism, arrived in Sochi weeks ago.
"Remember, the Boston bombers came out of this Dagestan-Chechen rebel area, so I think the threats are real," Rep. Michael McCaul, R-Texas, said.
CBN News terrorism analyst Erick Stakelbeck said the insurgents have links to al Qaeda and pose a threat not only in Russia but around the globe.
"Russia has fought two wars in Chechnya to keep them in the fold," Stakelbeck said. "And these guys are bloodthirsty, they're vicious, especially these Chechen terrorists."
Chechen rebels are well-known for recruiting women to train as suicide bombers. In 2010, two female suicide bombers killed about 40 people in attacks on the Moscow train station.
The dangerous North Caucasus region is one of the least evangelized places on earth. But some believers, like a woman named Sasha, are working in the shadows. These people say it's a risk worth taking to make the name of Christ known.
"Only Jesus can change lives and bring the hope people are looking for," Sasha told CBN News.
Islamists in the region carried out two attacks recently, and they're warning of more to come, including what they're calling a "surprise package" for visitors to the Olympics.
"If the games aren't attacked there will be attempts to attack, either the transit routes into the games or particular venues in the outlying areas," security expert Christopher Swift said.
Meanwhile, President Vladimir Putin says he will use whatever measures are necessary to ensure the Olympics are safe. More than 80,000 Russian troops are already deployed on the ground.