Washington DC - Thousands marched in US cities from Washington to Los Angeles on Saturday, demanding an immediate ceasefire as the war in Gaza nears the one-year mark, with a man attempting to self-immolate in protest.

The marches were part of a worldwide day of action against the devastating war, which has recently seen Israel intensify its military operations into Lebanon.

In Washington, more than a thousand angry protesters demonstrated outside the White House, with many demanding an end to the US military and other aid to its strategic ally, Israel.

"The US government has really shown what side of history it is on," said Zaid Khatib, an organizer with the Palestinian Youth Movement.

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"The US government has performed and co-signed the most evil atrocities that we've seen of this century."

Protesters waved Palestinian and Lebanese flags, among others, with many holding up signs and chanting in unison to demonstrate solidarity with the Palestinian cause.

Almost two hours into the protest, a man approached the demonstration site and attempted to set himself on fire, say eyewitnesses.

He succeeded in lighting his left arm ablaze before bystanders and police rushed to his aid, dousing him with water and extinguishing the flames using their keffiyehs, traditional Palestinian scarves.

"I'm a journalist and we neglect it, we spread the misinformation," he shouted in between screams of pain as the fire on his arm was put out.

Police said the man was being treated for "non-life threatening injuries."

In New York, thousands marched in the city's famed Times Square, some carrying pictures of people killed by Israel's military offensive in Gaza, which has left much of the territory in rubble.

Among those marching was Cornel West, a prominent rights activist and an independent candidate running in the US presidential election.

"I'm here to forever be in solidarity with people undergoing a vicious genocide," he said. "Dealing with ethnic cleansing it's getting worse, it's been a whole year now. You know, we got to keep fighting."