Japan on Monday released the 14 crew of a Chinese fishing trawler involved in a collision with two Japanese coastguard vessels in disputed waters last week, but kept its captain in detention. The incident has sparked a diplomatic row between the Asian powers, with China calling off planned talks over oil and gas fields in a contested area of the East China Sea and summoning Tokyo's ambassador four times to protest. Japan's top government spokesman Yoshito Sengoku said questioning of the crew had been completed, meaning there was no reason to keep them in Japan, and that prosecutors had also finished collecting evidence from the ship. "On Monday afternoon 14 people who had been investigated will be returned (to China) by charter plane, and the ship will be brought back, too, by an acting captain who will fly to Japan by charter flight," he said. The fishing boat's captain, 41-year-old Zhan Qixiong, was arrested Wednesday on suspicion of obstructing officers on duty — a charge that carries up to three years' prison, and a court has since approved his continued detention. "We will handle this as a criminal case based on Japanese domestic law," Sengoku told a regular press briefing. Tokyo suspects the trawler captain deliberately rammed the two Japanese vessels near the disputed island chain between Japan's Okinawa island and Taiwan, known as Senkaku in Japan and Diaoyu in China. Four Japanese patrol boats later pursued and seized the Chinese trawler. The uninhabited islands are claimed by Tokyo, Beijing and Taipei and are a frequent focus of regional tensions. There are four controversial Chinese gas fields in the sea that Japan says extend into its own exclusive economic zone. The row has cast a cloud over what had been a steady improvement in relations between the traditional East Asian rivals in recent years, as their economic relationship has deepened. The dispute escalated on Saturday when a Chinese vessel confronted two Japanese survey ships at sea, and Beijing called off talks with Tokyo set for later this month over their competing maritime claims in the area. The Chinese foreign ministry has said any evidence collected by Japan on the collision would be "illegal, invalid and in vain".