British police have arrested a third man over attempted bomb attacks on London.

The man was arrested on Saturday night as police hunted four men who tried to set off bombs on the city's transport system on Thursday. That failed attack came two weeks after suicide bombers linked by officials to al-Qaida killed 52 people.

Police arrested the man in south London, where two other men had been detained on Friday, a spokesman said.

Police have not suggested any of those held is one of the four prime suspects shown in closed-circuit television pictures released by police with an urgent public appeal for help.

The attacks have triggered fears among Londoners that they may be a long-term target for Islamist militants and sparked frequent security alerts, as commuters become alarmed over abandoned packages or people behaving suspiciously.

Police chief Ian Blair said police had no proof of a link between last Thursday's attacks and those two weeks before, apparently carried out by four British Muslim men who died in the blasts.

But the two sets of attacks share a common pattern, Blair noted. Both took place on three underground trains and a bus and both used home-made explosives, although those in the second wave failed to explode properly for reasons which are unclear.

The Observer newspaper also said two properties that police raided on Friday were linked to people with family connections in Somalia and Ethiopia.

Police were trying to establish how the first group of bombers, three of them Britons of Pakistani origin from northern England, might be linked to a second cell with African connections, the newspaper said.

Muslim leaders fear their community will be targeted after police identified the four July 7 bombers as British Muslims.

(China Daily July 26, 2005)