Thousands of pro-Palestinian protestors have demonstrated in London, urging the British government to stop the Israeli military from launching a ground operation in the Gaza Strip.

Participants marched to Downing Street on Saturday, waving Palestinian flags and chanting calls "Palestine will be free."

They criticized the British government, which has expressed its full support for Israel. They also demanded a halt to assaults on Gaza.

Leanne Mohamad, a British Palestinian human rights activist based in London, said she has friends who have families in Gaza, and that she is terrified for them.

The activist also said what is happening is "against humanity," and that it is a shame that "the world doesn't see it" and the British government is "actively supporting" it.

She called on Japan and the other international society to speak up against what she called an "atrocity."

About 1,000 police officers were deployed along the protest route. The Metropolitan Police had warned that they would crack down on shows of support for the Palestinian militant group Hamas or bids to intimidate the Jewish community.

Similar protests took place around the world on the same day, as concerns are growing about a large-scale military operation in Gaza, including a ground offensive.