South Korean police have used water cannons to disperse protesters in Seoul demonstrating against hundreds of job losses at a major construction company.

Hanjin Heavy Industries and Construction, which runs a major shipyard in Busan, has laid off some 400 workers.

At least 2,500 demonstrators gathered in South Korea's capital Saturday night for a new round of protests in the campaign “Hope Bus,” which is aimed at getting Hanjin to reinstate the workers. Protest organizers are also asking for legal punishment for company owner Cho Nam-ho.

Officials say police used water cannons after protesters broke into a restricted area. Protest organizers say they were trying to deliver a letter with their demands to President Lee Myung-bak.

About 9,000 police have been deployed in central streets to prevent violence.

Several left-leaning politicians have joined the rally in Seoul and a female activist in Busan is holding a sit-in protest atop a giant crane in the shipyard.

A July rally in Hanjin attracted about 10,000 protesters.