London, Oct 14 : Thousands of protesters have joined a pro-Palestine rally in London on Saturday amid the Israel-Hamas war, The Guardian reported. The march, which will progress to Whitehall, set off from Portland Place where pro-Palestine activists daubed the BBC's headquarters with red paint earlier on Saturday. The activist group Palestine Action claimed responsibility for targeting the building on Saturday morning, accusing the broadcaster of having 'Palestinian blood on its hands', The Guardian reported. Supporters at the demonstration let off red, green and black flares and chanted "Free, free Palestine" and "From the river to the sea, Palestine will be free". PA reports that tensions briefly boiled over between a protester and a member of the public on Regent Street. The march is organised by the Palestine Solidarity Campaign alongside a number of other groups: Friends of Al-Aqsa, Stop the War Coalition, Muslim Association of Britain, Palestinian Forum in Britain and the Campaign for Nuclear Disarmament, The Guardian reported. More than 1,000 officers have been deployed by the Metropolitan Police for the march and a Section 12 of the Public Order Act has been in force since midday covering the demonstration's route. Police have warned that anyone showing support for Hamas or deviating from the route could face arrest. /IANS