WASHINGTON - Rallies against the US-Israeli war on Iran swept numerous cities across the world over the weekend, with an estimated 8 million people turning out for over 3,300 protest events.

In the United States alone, thousands of demonstrations were held Saturday in major US cities, including Washington, New York, Los Angeles and San Francisco, and involved over 900,000 people, making it the largest single-day protest on record.

In Manhattan, New York City, tens of thousands of protesters marched along Seventh Avenue on Saturday afternoon, stretching more than 10 blocks, chanting slogans and carrying signs reading "No ICE," "NO Kings," and "No Wars."

Meanwhile, crowds gathered outside the Lincoln Memorial in Washington, DC and marched into the National Mall, holding signs reading "Regime change begins at home," "Defend Our Constitution". Demonstrators rang bells and played drums while chanting "No Kings!"

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According to local authorities, hundreds also showed up in deep-red cities, such as Midland in Texas and Lebanon in Pennsylvania.

Beyond US borders, people protested in Portugal, Greece, Japan, France, Britain and Italy, spilling an anti-war mood internationally.

In Portugal, about 200 Americans gathered on Saturday in front of Porto City Hall to protest against the US administration.

"We are against these policies of the current US government, both abroad and at home. And above all, against the war that is taking place in the Middle East. That war was ordered solely by (Donald) Trump and was not authorized by Congress," said Robert Glassburner, an American who has lived in Portugal since 1983.

In the Greek capital of Athens, a major rally began outside the parliament building and marched to the US embassy. Protesters called for an immediate end to the war in the Middle East.

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"We are here to send a message against the war," protester Eirini Thanou told Xinhua. "We do not want to be part of that war; we stand with people and peace."

Starting on Wednesday, over 24,000 demonstrators took to the streets in Tokyo, Japan, to condemn the US-Israeli military campaign against Iran, local media reported.

Despite rainy weather, protesters waved glow sticks and chanted slogans rejecting the use of force.

Several hundred people, mostly Americans living in France, joined for the first time by French labor unions and human rights organizations, gathered Saturday morning at the Place de la Bastille in Paris for a "No Kings" rally, media reported.

Xinhua correspondents witnessed Belinda Mullinix, a local protester costumed as the Statue of Liberty, holding a sign reading "NO KINGS SINCE 1776."

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Organizers estimated that as many as half a million people gathered in London on Saturday. Crowds marched through the capital toward Whitehall, many carrying placards reading "No to racism, no to Trump," as police officers lined the streets.

In Rome, crowds held up an enormous banner that reads "For a world free from war" in Italian, according to the Daily Beast, an American news website.

"Those who always pay the highest price in wars are the workers, the ordinary citizens, and all the most vulnerable groups of society," reported Daily Finland, quoting Marco, a protester at the rally.