MANILA, Philippines — A tropical storm roared toward Vietnam on Sunday after battering the Philippine capital and surrounding provinces, leaving 20 people dead in a region still soggy from three recent storms.

Typhoon Mirinae weakened Sunday as it headed over the South China Sea. It was expected to strike Vietnam's central coast around noon Monday.

Vietnamese Prime Minister Nguyen Tan Dung ordered residents to begin evacuating high-risk areas of five coastal provinces and ordered Vietnamese fishermen in the South China Sea to seek shelter immediately.

The two countries are still recovering from Typhoon Ketsana, which brought the Philippine capital, Manila, its worst flooding in 40 years and went on to kill more than 160 people in Vietnam in late September.

Ketsana and two later storms killed more than 900 in the Philippines. Some 87,000 people who fled the storms were still living in temporary shelters when Mirinae struck.

The latest typhoon left 20 dead, mostly from drowning, in six provinces. Four people were missing, disaster response officials said.