U.S. officials are concerned about the safety of the Olympic Games in Southern Russia.
An Islamic militant group that killed 34 people in recent bombings says that there are more attacks on the way.
In an internet video, the group claimed responsibility for Volgogard attacks and promised a quote "present" for those attending the Olympic Games.
The US State Department has already issued a warning to Americans planning to attend the winter games, saying they should stay vigilant and exercise good judgment using public transportation.
Lawmakers have serious concerns and want to see more security cooperation from Moscow.
"I think they think this is a politically embarrassing situation for them, and they are not going to share.”
That's really the wrong attitude, when we are talking about an interventional event.
Russian President Vladimir Putin says his country will do whatever it takes to keep the games safe.
Russia has reportedly spent around $50 billion on security.