Western intelligence agencies and analysts for years have been warning that al Qaeda and other terrorist groups are increasingly relying on a deadly weapon in their tool kits: female suicide bombers.
Those concerns were underscored Sunday when a suicide bomber, suspected to be a woman, detonated explosives at a busy railway station in the southern Russian city of Volgograd, killing at least 15 people and wounding dozens.
No group claimed responsibility for the attack, but suspicions have fallen on Islamist rebels from Chechnya.
“The use of female suicide bombers is a classic Chechen tactic, which is increasingly popular with other jihadist groups,” said Bruce Riedel, a former CIA officer who heads the Intelligence Project at the Brookings Institution in Washington.
The attack took place as Russia prepares to host the Winter Olympics in the Black Sea resort of Sochi in February and was the second terrorist attack in southern Russia in three days. A bomb in a parked car killed three people Friday in Pyatigorsk.
In June, Doku Umarov, the leader of the Islamist insurgency in the North Caucasus, lifted a moratorium on terrorist attacks inside Russia and in a videotaped message instructed rebels to use “maximum force” to disrupt the Winter Games.
“They are planning to hold the games on the bones of many, many Muslims buried on our land by the Black Sea. It is incumbent on us as Muslims not to permit that, resorting to any methods Allah allows us,” said Umarov, who is Chechen.
Sochi is about 250 miles from the republics of Chechnya and Dagestan, where the Islamist rebels are based. Volgograd, the city formerly known as Stalingrad and best known for a decisive Soviet World War II victory over Nazi Germany, is more than 500 miles from both restive Muslim republics.
“The Sochi Olympics are an extremely attractive target for al Qaeda and like-minded groups who want to bring attention to the Chechen cause,” said Mr. Riedel. “We should anticipate an effort to surge attacks on Russian targets at home and abroad in the next weeks.”
Female suicide bombers often exact higher tolls than their male counterparts simply because their movements are less scrutinized.
“To the extent security forces are looking mostly for male terrorists — which most terrorists have been — females are better able to evade scrutiny and slip into a crowd,” said Paul R. Pillar, nonresident senior fellow at Georgetown University’s Center for Security Studies.
“In some parts of the world, typical female clothing may be better able to conceal a bomb than is male clothing,” he said.
The Obama administration condemned “in the strongest terms” the attack in Volgograd, State Department spokeswoman Jen Psaki said Sunday.
“We send our sincere condolences to the families of the victims and stand in solidarity with the Russian people against terrorism of any kind,” she said.
Russian officials said the suicide bomber in Volgograd was a woman. One report identified her as Oksana Aslanova, a widow of a Dagestani militant.