China yesterday accused Vietnam of intentionally colliding with its ships in the South China Sea, but called for talks to end a bitter row over a Chinese oil rig.

A senior foreign ministry official in Beijing demanded Vietnam withdraw its ships after its southern neighbor said Chinese vessels used water cannon and rammed eight of its vessels at the weekend near the rig.

China said the drilling operations were being carried out in its territory and it had acted with the "utmost restraint" in using water cannons in response to rammings it blamed on Vietnam.

"It's the Vietnamese vessels that are provoking this issue. It's the Vietnamese vessels that are ramming into Chinese vessels," said Yi Xianliang, deputy director general of the foreign ministry's department of Boundary and Ocean Affairs.

Yi said China's operations in the waters were "completely legal, legitimate and justified" because the waters were China's inherent territory.

He said Vietnam had within five days dispatched 35 vessels that had rammed Chinese ships 171 times. He said the Vietnamese ships included armed vessels, but on the Chinese side there were only civilian or non-armed government vessels.

Yi said China stood ready to discuss the issue with Vietnam, "but the precondition is that Vietnam must put an end to the disruption of Chinese operations and must remove its vessel and personnel at the scene.

"Our aim, our only aim, is to guarantee our reasonable, legal, normal drilling operations," Yi said, adding that China had no choice but to increase its security measures in response to Vietnam's provocations.

Ngo Ngoc Thu, deputy commander of the Vietnamese coast guard, said the situation remained tense but there had been no contact yesterday.

"The two sides are still shadow boxing with each other," he said. Hanoi has hinted at international legal action and said it had requested dialogue with China's leadership, but was awaiting a response.

The row with its neighbor sent Vietnam's stocks markets plummeting.

The benchmark VN Index in Ho Chi Minh City closed down 5.9 percent, its biggest one-day fall in nearly 13 years, while the smaller Hanoi bourse dropped 6.4 percent, its biggest slump since May 2010.

Tensions are also brewing in another part of the sea, with China demanding that the Philippines release a Chinese fishing boat and its crew that were seized on Tuesday off Half Moon Shoal in the Nansha Islands.

Philippine police said the boat and its crew were seized for hunting sea turtles, which are protected under local laws.

Chinese, Vietnamese vessels collide

A Chinese vessel and two Vietnamese ships collided in water around the Xisha Islands where a Chinese company has deployed an oil rig, Vietnam said on Wednesday.

The foreign ministry in Hanoi said the collisions took place on Sunday and caused considerable damage to the Vietnamese ships. Six people sustained minor injuries, it said.

The China Maritime Safety Administration issued a navigational warning Saturday advising that Hai Yang Shi You 981, a China National Offshore Oil Corporation (CNOOC) owned drilling rig, would be operating from Friday to August 15, in a area south of Zhongjian Island in the Xisha Islands, which Vietnam claims as their own.

Vietnam deployed patrol vessels after the notice.

China's operation of its drilling rig 981 is legal, foreign ministry spokeswoman Hua Chunying said Wednesday at a regular press briefing.

She also urged Vietnam to stop disturbing China's exploration activities in its territorial waters.

Hua said operation of the drilling rig is lawful in China's territorial waters.

She said Vietnamese harassment of Chinese companies conducting normal activities runs counter to international law and basic norms of international relations as well as China's sovereignty and administration rights.

China's State Councilor Yang Jiechi had a phone conversation with Vietnam's Deputy Prime Minister and Foreign Minister Pham Binh Minh on Tuesday, demanding that the Vietnamese side stop disturbing Chinese companies' normal work in the Xisha Islands.

According to Vietnamese officials, dozens of navy and coast guard vessels from both countries are in the area where China has deployed the giant rig. Hanoi has strongly condemned the operation of the drilling rig in what it says are its waters in the South China Sea, and told CNOOC to remove it.

The United States on Tuesday said China's decision to move a deep-sea oil rig into disputed waters in the South China Sea was a "provocative" step which it was monitoring closely.

"We're looking carefully into this matter," State Department deputy spokeswoman Jen Psaki told reporters.

Hua said the Xisha Islands are part of China's inherent territory and the activities of the Chinese companies in the Xisha Islands are within the mandate of China's sovereignty and administration, which have nothing to do with Vietnam and the US.

The United States is in no position to make irresponsible remarks on China's affairs, Hua added.