About 40,000 pro-Palestinian demonstrators marched through central London, while thousands gathered in Paris, Rome, Manila, Cape Town and New York City.
Demonstrations were also held near the White House in Washington to protest US support for Israel in military campaigns in Gaza and Lebanon.
My message to mark one year since the October 7 attacks. — António Guterres (@antonioguterres) pic.twitter.com/0NPlHyAT6sOctober 5, 2024
Protesters at New York's Times Square chanted slogans including: "Gaza, Lebanon you will rise, the people are by your side."
They held banners demanding an arms embargo against Israel.
The war in Gaza was triggered when Palestinian Hamas militants attacked southern Israel on October 7, 2023, killing 1200 people and taking about 250 as hostages, according to Israeli tallies.
Israel's subsequent military assault on Gaza has killed almost 42,000 Palestinians, according to Gaza's health ministry.
It has laid waste to the enclave, displacing almost all of the 2.3 million population and causing a hunger crisis.
In Jakarta, the capital of Indonesia, the world's most populous Muslim-majority country, at least 1000 pro-Palestinian protesters gathered on Sunday morning near the US embassy demanding that Washington stop supplying weapons to Israel.
More protests were planned in several cities on Sunday.
In London on Saturday, counter-demonstrators waved Israeli flags as pro-Palestinian marchers walked by.
There were 15 arrests on the sidelines of the protests, according to police, who did not specify whether those detained were from either group.
US pro-Palestinian activists are protesting the war in Gaza opposite the White House. (AP PHOTO)
In Rome, police fired tear gas and water cannons after clashes broke out.
About 6000 protesters defied a ban to march in the city centre ahead of the October 7 anniversary.
In Berlin, a protest drew about 1000 demonstrators with Palestinian flags, who chanted: "One Year of Genocide".
The war in Gaza has led to genocide allegations against Israel at the World Court, which Israel denies.
German demonstrators also criticised what they called police violence against pro-Palestinian protesters.
Israel supporters in Berlin protested against rising anti-Semitism.
Scuffles broke out between police and pro-Palestinian protesters.
During the past year, the scale of the killing and destruction in Gaza has drawn some of the biggest global demonstrations in years, including in the US, where there were weeks of pro-Palestinian college campus encampments.
Advocates have raised concerns over anti-Semitic and Islamophobic rhetoric in some protests and counter-protests related to the conflict.
Police in Rome fired tear gas and water cannons at protesters after clashes broke out. (AP PHOTO)
Rights advocates have warned about rising threats against Muslims and Jews around the world.
The US and other allies have supported Israel's right to self-defence, but Israel has faced wide international condemnation over its actions in Gaza, and now over its bombarding of Lebanon.
Prime Minister Benjamin Netanyahu says his government is acting to prevent a repeat of the October 7 assault by Hamas.
The war in Gaza has spread through the region, drawing in Iran-backed groups in Lebanon, Yemen and Iraq.
Israel has sharply escalated a campaign in recent weeks in Lebanon.
Iran launched a barrage of missiles against Israel this week to which Israel has not yet responded.
"We fear a regional war, because there are tensions with Iran at the moment, and perhaps with Iraq and Yemen," Lebanese-French protester Houssam Houssein said in Paris.
"We really need to stop the war because it's now become unbearable."
In Manila, activists clashed with anti-riot police after they were blocked from holding a demonstration in front of the US embassy in the Philippine capital against Washington's support for Israel.
