BEIJING - Chinese fishermen hunting sea turtles were captured Wednesday by Philippine maritime police, and Chinese and Vietnamese ships collided near an oil rig in a volatile day on the troubled waters of the South China Sea.

No serious injuries were reported in the incidents, hundreds of miles apart, but the coincidence was an indication that tensions in the region have not abated despite the international cooperation during the hunt in March for the missing Malaysian jetliner.

In the incident in the Philippines, Chinese state media initially reported that 11 fishermen were abducted Wednesday morning by armed men, implying that it was a case of piracy.

"Several armed men forced themselves onto the boat and fired four or five shots in the air. They then took control of the boat," a fishing association based on China's southern Hainan Island was quoted as telling the New China News Agency.

But the Philippine National Police quickly rebutted the statement, saying that the Chinese fisherman had been caught with 800 sea turtles, which are protected under Philippine law. The incident took place near the Spratly Islands' Half Moon Shoal, which the Philippines claims is within its 200-mile exclusive economic zone.

Maritime police confiscated two Chinese boats, which are being towed to Puerto Princesa, police said in a statement.

Meanwhile, dozens of Vietnamese and Chinese ships, along with helicopters, were facing off near a giant oil-exploration rig operated by China's state-owned oil company.

In Hanoi, Vietnamese officials held a news conference Wednesday to release videos and photographs of what they described as Chinese ships deliberately ramming and using water cannons against Vietnamese patrol boats.

Since the weekend, the Vietnamese said, eight of their boats had been "rammed, hit or sprayed with high-pressure hoses . . . damaging Vietnamese vessels and injuring their crew members."