The coast guard said the 1,400-ton Yunxing with eight Chinese and one from Myanmar aboard caught fire early Friday, two nautical miles from Busan.

Four Chinese died and the rest of the crew was pulled to safety, a Busan coast guard spokeswoman told AFP.

The blaze was put off in about two hours but heavy smoke delayed a rescue operation.

Coast guard officials suspect the blaze might have been caused by a short circuit, Yonhap news agency said, adding there was no cargo aboard.

One rescued sailor told investigators that the fire had started around the first floor kitchen, Yonhap said.

Coast guard officials believe that smoke had hampered a quick evacuation of the sailors who were sleeping at the time of the fire. The bodies were found in the first floor kitchen and a second floor cabin.