Seven people were arrested as thousands gathered in central London on Saturday to protest Israel's 15-month war on Gaza, a day after a ceasefire agreement with Hamas.

Protesters gathered in Whitehall holding signs reading "Stop Arming Israel" and "Free Palestine". A week ago, police restricted organizers' plans to gather outside BBC Broadcasting House due to its proximity to a synagogue.

Crowds were initially blocked from marching from Whitehall towards Trafalgar Square by a line of police, but protesters broke through police lines and advanced towards the central London landmark.

Video posted on X appeared to show protesters including former Labor leader Jeremy Corbyn and former shadow chancellor John McDonnell passing police as the crowd walked towards Trafalgar Square.

Police blocked entrances and exits to the square to contain the protests, the Palestinian Authority reported. The Metropolitan Police posted on X: "The group of people who forcibly broke through the cordon are now being held in the northwest corner of Trafalgar Square.

"Anyone in the group should now disperse and leave the area. Anyone who continues to breach conditions or incites further breaches will be arrested."

According to the Met, seven people were arrested during the protest, four on suspicion of public order offences, and two on suspicion of breaching protest conditions. One of the conditions prevented participants from entering a specific area around Portland Place.

A seventh person was also arrested on suspicion of holding a placard suggesting support for a banned group, the Met said.

The demonstrations, which began days after the attack on October 7, 2023 and have continued each week as the war raged on - making it one of the largest protest movements in recent British history - called for to end the conflict, which has left more than 10 people dead. Israeli attacks have left 46,000 Palestinians stranded in Gaza, according to Gaza health officials.

"For 15 months we have marched, rallied and protested in towns and cities across the UK with one of our core demands being a ceasefire and now we stand on the brink of a ceasefire committing to an end to the immediate and catastrophic killing of the Palestinian people," Palestine Solidarity Athletic Director Ben Jamal said.

On Friday, the Israeli government approved a ceasefire deal that would replace dozens of hostages held by Hamas with Palestinians in Israeli jails and suspend the war for an initial six weeks. The agreement will take effect on Sunday.

Last week, the Met banned marches from gathering outside the BBC's London headquarters because of its proximity to a synagogue. Protesters plan to gather outside Broadcasting House before heading to Whitehall.

The British Palestine Forum said it "categorically rejects" the Met's attempts to move the protest to Russell Square and threatened to arrest individuals who rallied elsewhere. The groups said the protest was able to go ahead as planned in Whitehall after "enormous public pressure".