New Delhi: In London, around 20,000 protestors waving banners and Palestinian flags and confronted with police in riot gear outside the Israeli embassy.
In Germany, 40,000 people took out marches. Demonstrations in Paris where about 30,000 took to the streets ended with people clashing with the police.
Meanwhile, Israeli air force dropped leaflets over Gaza warning residents of more strikes and telling them to stay indoors.
An estimated 820 Palestinians and 13 Israelis have been killed in 16 days of strikes.
Latest agency reports say that Israeli tank fire killed five Palestinians, at least four of them civilians, in the northern Gaza Strip on Sunday as per reports from medical workers.
They identified the dead from the incident in Beit Lahiya as four women and a man from two different families.
But Israel and Hamas have vowed to continue fighting despite international calls for an end to the conflict.
Hamas' leader in exile, Khaled Meshaal has said truce is not an option until Israel ends its military offensive and lifts the blockade of Gaza.
Israel isn't listening, though. Its tanks have pushed deeper into the Gaza strip.
Israel also threatened to intensify its air and ground assaults on Hamas militants who in turn lobbed more rockets on the Jewish state.
The conflict which is almost 16 days old, has already claimed over 846 Palestinian and 13 Israeli lives.
(With inputs from CNN-IBN and Reuters)