Thousands of pro-Palestinian protesters marched in London and Paris on Saturday, calling out against Israel’s military operation in the Hamas-controlled Palestinian enclave.

At least 10,000 protesters marched through central London for the second week running on Saturday. A police source estimated the crowds at 10,000, but an AFP photographer suggested the number could be far higher, forcing the closure of roads around Britain’s parliament.

Demonstrators held placards reading “Stop Israeli State Terror!”, “Freedom for Palestine” and “Gaza — End the Siege.” They also chanted “Shame on you David Cameron” as they filed past the British prime minister’s Downing Street office.

The crowds took over Parliament Square, where a series of speakers, including Roxy Music member Brian Eno, took to a temporary stage to call for an end to the military campaign, which has claimed more than 1,000 lives, according to Palestinian figures from Hamas run Gaza. Israel says hundreds of the dead are militants and terrorists.

Forty Israeli soldiers and three civilians have been killed in the fighting.

A demonstrator with a painted face marches through the streets from outside the Israeli embassy in central London on July 26, 2014 (Photo credit: Justin Tallis/AFP)

A demonstrator with a painted face marches through the streets from outside the Israeli embassy in central London on July 26, 2014 (Photo credit: Justin Tallis/AFP)

One speaker urged demonstrators to buy the song “Freedom for Palestine” by One World in the hope that it would enter the top singles chart and receive radio air play.

Meanwhile more than 1,000 protesters gathered in central Paris Saturday shouting slogans against Israel despite an official ban on the rally as hundreds of riot police stood by to stop it from going ahead.

Organizers of Saturday’s protest had tried going to court to get the ban overturned, but they were unsuccessful and Interior Minister Bernard Cazeneuve warned Saturday that they would be held “responsible for any unrest… and liable to penal sanctions.”

According to initial estimates, some 1,500 people turned up mid-afternoon at Republic Square in Paris, brandishing Palestinian flags and the red banners of the far-left New Anticapitalist Party that had called on people to brave the ban and come anyway.

Some 2,000 police were mobilized, and many of them were present on the square to stop the rally from moving on to other parts of the French capital.

“Israel clear out of Palestine, the era of colonies is over,” “Israel assassin, Hollande accomplice,” “Israel, piss off, Palestine isn’t yours” were just some of the slogans shouted by protesters.

The Israeli operation in Gaza — launched to stop rocket-fire from the Strip and in order to deal with the threat of terror tunnels dug across the border by Hamas — has stirred up huge passions in France, home to the largest Muslim and Jewish communities in western Europe with around five million Muslims and half a million Jews.

And while many protests around the country have been peaceful, three demonstrations in Paris and the suburb town of Sarcelles descended into chaos. In Sarcelles, Jewish businesses were looted and in one violent Paris demonstration, protesters tried to storm two synagogues, raising concerns among the Jewish community about anti-Semitism

US Secretary of State John Kerry and top diplomats from Europe and the Middle East meeting in Paris on Saturday called for an extension to a temporary truce currently in force between Israel and Hamas.

New British Foreign Secretary Philip Hammond later insisted there was an “absolute humanitarian necessity” to extend the ceasefire.

Hamas has fired over 2,000 rockets at Israel over the past 18 days. Six IDF soldiers have been killed by Hamas gunmen emerging from tunnels inside Israel in five attacks this month.

Times of Israel staff contributed to this report.