More than 30 Chinese fishermen were missing after two boats sank Tuesday when a strong typhoon hit South Korea, coastguard officers said.

A total of 31 crew members were aboard the boats which went down in gale-force winds and high waves off the southern island of Jeju, they said.

An earlier report by the Yonhap news agency had placed the figure at 34.

The state weather agency issued a typhoon warning early Tuesday for Seoul, the capital of about 10 million people, as the storm named Bolaven continued moving northwards.

The typhoon brought heavy rain and strong winds to southern and western areas of the country, cutting power and bringing down street lights and church spires.

Schools in Jeju were closed or reduced classes Monday and many schools in other provinces were to be closed Tuesday, Yonhap reported.

The US and South Korean military called a temporary halt to a large-scale joint military exercise that began last week, the news agency said.