"We are sick and tired of the bloodshed nonstop wars. This is wrong, this is immoral, and this is a crime against humanity," said Yehuda Littmann, a protester from New York.

NEW YORK, March 3 (Xinhua) -- The U.S.-Israeli attacks on Iran sparked a wave of nationwide protests in around 50 cities across the United States on Monday, as heightened tensions in the Middle East have stretched for days.

The conflict has the potential to quickly expand into a devastating regional war which will bring unthinkable death and destruction, Answer Coalition, one of the organizers of the protests, said in a statement issued on Monday.

"Already, other countries in the region have been drawn into the war. (U.S. President Donald) Trump is lying when he says that Iran poses any kind of threat to the United States," said the statement.

Answer Coalition, which stands for Act Now to Stop War and End Racism, called for a mass anti-war movement to "put an end to this destruction."

The United States and Israel began massive airstrikes against Iran on Saturday morning, triggering Iran's retaliatory missile and drone attacks on Israel and U.S. assets across the Middle East.

Trump said on Monday the military campaign against Iran has "capability to go far longer" than four to five weeks.

Hundreds of people rallied at Columbus Circle in Manhattan, New York City, calling on Trump's administration to end Washington's military involvement in Iran.

This was the second major protest in New York City in recent days against the U.S.-Israeli joint airstrikes targeting Iran. Speaking at the rally, protesters expressed strong opposition to the ongoing military action.

"The attack that the United States waged on Iran was not only illegal against international law, but ... also unprovoked," said Gabriela Silva, a volunteer with Answer Coalition.

The attack left many dead, "including little girls and their teachers at school," Silva added.

On Saturday, a girls' school in Iran's southern province of Hormozgan was targeted in the Israeli and U.S. attacks, leaving at least 165 people killed and 95 others wounded.

The U.S. attack on Iran does not protect the interests of American people, and the proposed over-1 trillion U.S. dollar-budget that the United States spends on war, death and destruction should be invested in sustaining life for people here, Silva said.

Carrying Iranian flags and banners, a group of protesters gathered outside the White House on Monday evening in protest of the strikes against Iran.

"We are sick and tired of the bloodshed nonstop wars. This is wrong, this is immoral, and this is a crime against humanity," Yehuda Littmann, a protester from New York, told Xinhua. "I'm Jewish. I'm embarrassed."

He added that the United States is now becoming involved in another war, which he said would harm the lives of ordinary Iranians as well as working-class Americans like himself.

"It's already causing death. It's already causing chaos. It's not the right way to go about whatever they're doing," Malinda Dunn, a protester from New York, told Xinhua.

"The administration's not even going to Congress. We need to stop whatever we were doing in Iran. Nobody knows what they're doing. There's no goal. There's no plan. My feeling is I hope our Congress gets back and can stop this madness," Dunn said.

On the West Coast, hundreds of people took to the streets in San Francisco, San Jose and other major Bay Area cities during the anti-war protests in the evening as part of a coordinated day of action around the country.

Representative Lateefah Simon, who represents Berkeley and other East Bay cities in Congress, swiftly condemned the military actions. "The attacks by the United States and Israel on Iran absent Congressional approval demonstrate once again President Trump's callous disregard for the rule of law," she posted on social media platform Bluesky.

A further round of nationwide protests is scheduled for March 8, according to organizers.