London, Sep 7 - An elderly Kolkata-born man died in a London hospital Monday after a gang of teenage schoolboys beat him viciously in a suspected race attack.

Retired care worker Ekram ul Haque, 67, was battered to the ground in front of his five-year-old granddaughter as they returned from a south London mosque.

Three boys, aged 12, 14 and 15, have been charged with assaulting Haque and a man in his 40s - just minutes earlier - in Tooting, a south London neighbourhood that is home to many people from West Bengal and Bangladesh.

Haque's granddaughter Marian was unhurt and was able to give a detailed account of the Aug 31 incident.

Murder squad detectives have linked the attack with attempted assaults on two other elderly South Asians in Tooting a week earlier and charged the 15-year-old boy in connection with them.

All three attackers are black and wore hooded tops as they carried out their assaults.

Graphic images of the attack were caught on CCTV, and police have had to step up security at the mosque following growing tensions in the local community.

Scotland Yard confirmed that the assault was being treated as 'racially motivated'.

Haque, a devout Muslim, was returning home after attending evening prayers during the holy month of Ramadan, when the teenagers ran up behind him and clubbed him around the head.

Two other worshippers chased the thugs away but Haque suffered horrific head injuries.