Vietnam has accused China of assaulting its fishermen in the South China Sea, in the countries’ latest spat over disputed territory believed to be rich in natural resources.

Foreign Ministry spokesman Luong Thanh Nghi said the Chinese action “seriously infringed upon Vietnam’s sovereignty and “gravely threatened lives and caused heavy property losses.

The state-controlled newspaper Vietnam News reported Thursday that China used force to threaten 11 Vietnamese fishermen on Feb. 22, preventing them from entering the Paracel islands to avoid a storm. It said Chinese forces assaulted the fishermen and tried to take their property.

Vietnam lodged a protest with the Chinese Embassy in Hanoi, demanding compensation for the fishermen and an end to the attacks, Nghi said in a statement posted late Wednesday on the ministry’s website.

Chinese Foreign Ministry spokesman Hong Lei denied the fishermen were assaulted, saying Chinese authorities simply compelled Vietnamese ships to leave Chinese-claimed waters near the Paracels, which it calls the Xisha Islands.

“We call on Vietnam to pay real respect to China’s sovereignty over the Xisha Islands and take effective measures to step up education and management of Vietnamese fishermen and stop illegal fishing activities to preserve China-Vietnam relations, Hong told a regular briefing in Beijing on Thursday.

The contested islands lie near vital shipping lanes and are believed to be rich in oil and gas. China claims nearly the entire South China Sea, while Vietnam and other Southeast Asian countries claim some areas.

Last summer, tensions rose as Vietnamese staged rare protests in Hanoi over allegations that China interfered with Vietnam’s exploration activities in the sea. Beijing denied the charge.

China has occupied the disputed Paracels since 1974, but Vietnam claims sovereignty. The U.S. has said it has a national interest in ensuring freedom of navigation in the area.

Last month, the U.S. Congress said it would approve the transfer of a second ship to the Philippines to help its navy defend its waters following spats with China over territory in the South China Sea.

2012 The Associated Press