They congregated at Victoria Embankment on Saturday afternoon before making their way to Hyde Park.
Holding banners, placards and flags, the demonstrators let off green and red-coloured smoke and chanted, blocking traffic as they marched.
Protesters let off coloured smoke (Yui Mok/PA)
The protests came after an 11-day military offensive between Israel and Palestine in the Gaza Strip.
Some demonstrators could be seen wearing costumes, masks and face paint, while others were draped in the Palestinian flag.
Groups of police watched as some protesters climbed bus stops and lampposts and wrote “Free Palestine” on walls.
Chants of “Israel is a terrorist state” and “We are all Palestinians” could be heard during the march.
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Israel-Hamas ceasefire holds as humanitarian aid arrives in Gaza while thousands march in London
A ceasefire between Israel and Hamas is continuing to hold, allowing the first aid convoys to reach Gaza.
The truce, which began before dawn on Friday, is allowing both sides to assess the damage following 11 days of conflict in which
Israel pounded
Gaza with airstrikes and militants fired thousands of rockets at Israel.
Gaza medical officials said 248 Palestinians - including 66 children - were killed, while the latest death toll in Israel is 13, according to Reuters news agency.