San Francisco Frontiers - Pro-Palestinian protest blocks San Francisco's Golden Gate bridge

Protest group A15 Action said it was coordinating a "multi-city blockade... in solidarity with Palestine."

"In each city, we will identify and blockade major choke points in the economy, focusing on points of production and circulation with the aim of causing the most economic impact," the group said on its website.

Demonstrators who were blocking traffic on the Golden Gate Bridge held a banner reading "Stop the world for Gaza."

Aerial footage showed stationary traffic in one direction on the massive bridge, while lanes in the other direction were empty, with police present.

A15 Action's website said action was planned for places as far apart as Mexico City, Ho Chi Minh, Sydney, Athens, New York and Johannesburg.

"There is a sense in the streets in this recent and unprecedented movement for Palestine that escalation has become necessary: there is a need to shift from symbolic actions to those that cause pain to the economy," it said.

A protest earlier on Monday blocked a highway heading into Chicago's O'Hare International Airport.

Israel launched its punishing offensive in Gaza last October after an unprecedented attack by Hamas militants resulted in the deaths of 1,170 people, mostly civilians, according to Israeli figures.

Over 33,000 people have since been killed in Gaza, mostly women and children, according to the health ministry in the Hamas-run territory.

Monday's protest on the Golden gate Bridge came as the Middle East was facing some of its most precarious moments in the last six months, after Iran launched a large-scale aerial attack on Israel over the weekend.

The attack was largely fended off by Israel, with help from allies including the United States and Britain.

Israel is weighing its response to the attack, which Tehran said was in retaliation for a presumed Israeli strike on an Iranian consulate building in Syria that killed a top general.

US President Joe Biden said Monday he was working to prevent conflict spreading.

"The United States is committed to Israel's security. We're committed to a ceasefire that will bring the hostages home and prevent the conflict from spreading beyond what it already has," Biden told reporters.

Western leaders such as Biden find themselves in a difficult position over their support for Israel.

While the stance is popular among some voters, others -- often younger people -- believe the government of Israel is carrying out acts of genocide as part of its offensive in Gaza.

The issue is expected to weigh on the ballot box in November, when Biden fights for reelection against Republican Donald Trump.

Z.Phillips--SFF