Three British residents may have been involved in last month's attack in Beslan, and one of them may have escaped the school only to be detained on the Russian-Azeri border, British newspaper The Observer reported, citing sources in the Russian security services. One of the possible hostage-takers, Kamel Rabat Bouralha, a 46-year-old British citizen, was arrested while trying to cross the Russian-Azeri border, The Observer reported Sunday. The newspaper quoted Scotland Yard as saying that Bouralha had attended a Finsbury Park mosque in London known for its radical Islamic preaching.Major General Ilya Shabalkin, federal forces spokesman for the North Caucasus, confirmed by telephone Monday that Bouralha had been detained at the Dagestani border with Azerbaijan, but declined to comment whether he had played a role in the Beslan attack. If confirmed, Bouralha's participation would cast doubts on earlier statements by the Prosecutor General's Office that none of the terrorists had escaped from Beslan. Federal authorities' assessments of the number and origin of the hostage-takers have been revised many times. Deputy Prosecutor Sergei Fridinsky initially said that Chechens, Ingush, Uzbeks, Kazakhs, Koreans and even a black man were among the hostage-takers. Later it was discovered that the black man was only covered with soot. Most of the 33 hostage-takers have now been identified by the authorities, but not all of their names have been released. The Observer said they include two Algerians in their mid-30s, Osman Larussi and Yacine Benalia. Both were thought to have lived in London until recently, but it is not known whether they were British citizens, The Observer said. Oleg Vershinin, spokesman for the Federal Security Service in North Ossetia, and Sergei Probkov, spokesman for the Prosecutor General's Office in the North Caucasus, declined to comment on the report when reached by telephone Monday.