Protesters calling for a ceasefire in the Israel-Hamas conflict have blocked the San Francisco Bay Bridge, a key commuter route into the city that is hosting the Asia Pacific Economic Cooperation (APEC) forum, Reuters reports.

Organizers said 200 people attended the demonstration, which also called for an end to US military aid to Israel. Police had arrived and formed at least one riot line, according to a social media post from one of the organisers.

Local emergency services warned of the blockage during morning rush hour on the bridge which links Oakland and other East Bay cities to San Francisco.