HANOI, Vietnam — Vietnam and China traded accusations Tuesday over who was the aggressor in a clash that led to the sinking of a Vietnamese fishing boat in the South China Sea, where tensions have been high after China moved an oil rig into the disputed waters.

Hanoi accused a Chinese vessel of ramming the wooden Vietnamese boat Monday before fleeing the scene. Beijing said the Vietnamese boat was trying to get close to the oil rig, rammed into one of its vessels and then sank. The crew was rescued.

The clash occurred about 18 miles south-southwest of the large oil rig that China deployed May 1 in waters both nations claim.

The rig deployment infuriated Hanoi and set off violent anti-China protests that further soured ties between the neighboring communist countries with close economic relations. Vietnam sent patrol ships to confront the rig, and China has deployed scores of vessels to protect it.