(AP) The chairman of the House Homeland Security Committee says safety measures undertaken by the Russian government at the Sochi site of the Olympics are the "most impressive" in the history of the Games.
But Texas Republican Rep. Michael McCaul says he remains concerned about the possibility of an attack at the Games, which commence on Feb. 7.
McCaul tells CNN Wednesday he believes improvement is needed in intelligence-sharing between Russia and the United States. And he voices concern about the risk of a suicide bomber setting off an explosive device.
McCaul visited the site last week. He calls it "quite fortified" but says that "it only takes one suicide bomber to get in."
He says, "I would hope the president of Russia would allow us to come in and help."
Hungary's Olympic Committee says it has received an email message written in Russian and English threatening its athletes with terrorist attacks at the Sochi Olympic Games.
The International Olympic Committee confirmed there was a message but downplayed the severity of it.
Bence Szabo, secretary general of the Hungarian Olympic committee, told the sports daily Nemzeti Sport on Wednesday that the message also urged the Hungarian delegation to stay away from the Winter Games, which run from Feb. 7-23.
Committee President Zsolt Borkai told the state news wire MTI that other countries' Olympic committees had also received similar messages and that the IOC, Sochi organizers and Hungarian security forces had been informed.
The IOC repeated its stance that it "takes security very seriously."
"(We will) pass on any credible information to the relevant security services," the IOC said in a statement. "However, in this case it seems like the email sent to the Hungarian Olympic Committee contains no threat and appears to be a random message from a member of the public."
A spokeswoman for the Switzerland's Olympic committee said similar threats were "normal" so close to the Winter Games and that athletes and officials would base their travel plans on the assessment of security and diplomatic officials.
"This is kind of an everyday mail. This is normal before every Olympics," Martina Gasner told the AP by telephone. "We work with the federal offices for police and foreign relations."
"If they say you can go to Sochi, we will go, and if one day they will say it is too dangerous and we command you not to go then we will change our plans," she said.
The Hungarian Olympic committee did not immediately respond to AP requests for comment.
President Barack Obama and Russian President Vladimir Putin are discussing how to have a safe and secure Olympics in Sochi. The White House says the U.S. is offering its full assistance.
Obama and Putin spoke by phone on Tuesday amid security concerns for next month's Olympics.
Russian officials are hunting down three potential suicide bombers, including one believed in be in Sochi. The State Department is telling those attending the games to remain attentive to personal security. U.S. lawmakers have also expressed serious concerns.
The White House says Obama and Putin also discussed Syria's civil war and preparations for the peace conference starting this week in Switzerland, plus efforts to destroy Syria's chemical weapons.
Cooperation on Iran and the interim nuclear deal taking effect this week were also discussed
Russian security officials are hunting down three potential female suicide bombers, one of whom is believed to be in Sochi, where the Winter Olympics will begin next month.
Police leaflets seen by an Associated Press reporter at a central Sochi hotel on Tuesday contain warnings about three potential suicide bombers. A police letter said that one of them, Ruzanna Ibragimova, a 22-year-old widow of an Islamic militant, was at large in Sochi.
A U.S. congressman who was in Sochi on Tuesday to assess the situation said he was impressed by the work of Russian security forces but troubled that potential suicide bombers had gotten into the city, despite all of the extraordinary security measures.
"We know some of them got through the perimeter," Rep. Michael McCaul, chairman of the U.S. House Homeland Security Committee, told The Associated Press. "She's for real. What we don't know is how many more black widows are out there."
Russian authorities have blamed the so-called "black widows" of slain insurgents for previous suicide attacks in the country.
The Black Sea resort town will host the games amid concerns about security and potential terrorist attacks.
The southern city of Volgograd was rocked by two suicide bombings in late December, which killed 34 and injured scores more. An Islamic militant group in Dagestan posted a video on Sunday claiming responsibility for the bombings and threatened to strike the games in Sochi, about 500 kilometers (300 miles) west of Dagestan.
McCaul, a Republican from Texas, said he had numerous meetings with officials in Moscow and Sochi, and was briefed by the joint operation center in Sochi, which is responsible for overall security in the area.
"The one improvement I would ask of the Russians is to allow our intelligence services to coordinate and cooperate better with theirs," McCaul said. Although the Russian side was confident that it could provide security, the U.S. has information that could help keep the games safe, he said.
The congressman also expressed concern that terrorists could have gotten into Sochi before security was tightened.
"How many potential cells could be in Sochi and the Olympic village?" he said. "But after `the ring of steel' was implemented we have this one person who seems to have been able to penetrate it. It does demonstrate vulnerability."
Police material distributed to the hotel staff included pictures of two other women in veils: 26-year-old Zaira Aliyeva and 34-year-old Dzhannet Tsakhayeva. It said they had been trained "to perpetrate acts of terrorism."
It warned that the two women "are probably among us," but, unlike Ibragimova's case, did not say if they are in Sochi.
No further information was provided about the two women or their motivation. The term "black widow" refers to the belief that women who have carried out past suicide attacks in Russia did so to avenge the deaths of husbands or other male relatives.
Security officials in Sochi were not available for comment on Tuesday.
The Olympics are to be held Feb. 7-23. Russia has mounted an intense security operation in the city, but concern persists that "soft targets" outside the Olympic venues, such as buses and tourist facilities, are vulnerable to attack.
Russian troops also have been active fighting militants in Dagestan, one of the predominantly Muslim republics in Russia's North Caucasus and the center of an Islamic insurgency that has engulfed the region.
On Tuesday, troops shot dead the leader of a militant group, Interior Ministry spokeswoman Fatina Ubaidatova said. She said the militant, Eldar Magatov, was wanted in attacks on security forces, bombings and the extortion of businessmen.
Interior Ministry troops elsewhere in Dagestan defused an explosive device placed near a village administration building and engaged in a firefight with militants holed up in a house, the spokeswoman said.