The demonstration, organized by Stop the War Coalition, The British Muslim Initiative, The Palestine Solidarity Campaign and Lebanese community associations, marched towards the U.S. embassy in Britain before reaching the Parliament Square for a rally.

The demonstrators chanted slogans such as "ceasefire now", and carried makeshift children's coffins to symbolize the deaths in the conflict.

They also planned to deliver a letter with 40,000 signatures to the Downing Street, urging British Prime Minister Tony Blair to work towards an unconditional ceasefire in Lebanon.

"We therefore call on the Government to change its position and join the vast majority of the world's general states, the U.N. Secretary General and the Archbishop of Canterbury in calling for an immediate ceasefire in Lebanon to save lives and prevent the destruction of that country", the letter says.

Meanwhile, more than 110 Labor members of Parliament have signed a petition calling for a halt to the Israel-Lebanon conflict. The petition shows the Labor's unrest over Blair's handling of the Middle East crisis.

On Friday, Blair delayed his annual summer holiday to continue efforts to reach a United Nations Security Council resolution to end the conflict.