A bomb-threat warning was carried on the front page of this week's Pink Paper, a weekly gay newspaper published on Thursday. Police and the Home Office have also urged gay businesses and organisations to be on the alert.

Security was also stepped up in Brighton, and Manchester's Canal Street, which are both popular gay areas.

Friday evening's bomb blast at a gay bar in Old Compton Street, Soho, which has killed three people and injured 30 seriously, has hit an area popular not only with gays, but also with theatre-goers, clubbers and diners.

Rescue workers help wounded people past a fire engine

A spokesman for the Pink Paper told BBC News Online: "We are very shocked, very upset by this.

"We do not understand it. People are out on a Friday night to meet their friends in the West End - it's terrible."

Only a handful of staff were left at the paper's offices after the bombing, as a number of others had gone to the scene of the blast to see if they could help.

A bomb warning was also carried on the Equality Alliance's Website on 26 April, under the headline Combat 18 bomb threat. The site describes itself as "an impartial news relaying service for lesbian, gay, bisexual and transgender news stories".

Warning issued

The warning reads: "Intelligence sources have advised that Combat 18 were almost certainly behind the two recent explosions in London.

"There is a possibility that the group will also attempt to target the gay community."

Vigilance in gay areas is advised, and people are warned to look out for suspicious people or unattended bags.

It continues: "Do not be embarrassed about false alarms - the LGBT community has every right to take extra precautions given the stated objectives of Combat 18."

Appalling atrocity'

Stonewall, the lesbian and gay lobby group, said it received a warning urging vigilance, on Friday morning from the Metropolitan Police. It said the message was also sent to many other gay organisations.

Angela Mason, executive director of Stonewall, said: "This is an appalling atrocity. We hope that all those injured will make a full recovery as quickly as possible.

"We extend our sympathies and good wishes to those injured in the bombs which have already been targeted at Britain's black and Asian communities."

This latest explosion comes in the wake of two nail bomb attacks in London's Brixton and Brick Lane during the past fortnight.

Last Saturday six people were hurt in Brick Lane and 39 were injured in Brixton the previous weekend.