(CBSNews.com) - In a phone call Tuesday, President Barack Obama offered Russian President Vladimir Putin full U.S. assistance in preventing a terrorist attack the Sochi Olympics.
Sochi is in the Caucasus region, not far from Dagestan and Chechnya, where militants are fighting to break away from Russia.
The Russians are scouring the region for potential terrorists, some of them women.
The latest pre-Olympic anti-terror event, Russian style: a shootout in Dagestan, a few hundred miles from Sochi.
Russia's National Anti-Terror Committee says a senior militant was killed in this raid. It was just one of a number of anti-terror operations under way in the Caucasus region. Yet, the Russians are still worried.
They circulated a poster in Sochi warning of the possible presence of two more "black widow" suicide bombers -- women whose militant husbands or brothers have been killed by security forces and who may be seeking revenge.
Except the woman on the left in the poster -- Zaira Aliyeva -- may already be dead.
The Russians say she was killed along with six other people in this assault, also in Dagestan, this past weekend.
The fear of black widows stems from what the Russians claim has been their involvement in previous terror attacks, such as the 2002 Moscow theater siege where more than 100 people died. The Russians say women with suicide vests were found among the dead. Black widows were also involved in the 2010 Moscow subway bombing where at least 40 people were killed.
Now Russian authorities are trying to find Ruzanna Ibragimova, the first black widow suspected of being in Sochi -- and who, they fear, is waiting to strike.
The Russians may have some American help in countering the terror threat. The Pentagon says it's in discussions with Moscow about providing technology -- developed in Iraq and Afghanistan -- for jamming phone signals used to set off explosive devices.
But there are still technical issues to overcome -- and there isn't much time. The Olympics start on Feb. 7.
© 2014 CBS Interactive Inc. All Rights Reserved.