Beijing: China piled more pressure on Tokyo on Sunday in a row over a fishing boat incident in disputed waters, summoning the Japanese ambassador in the early hours of the morning.
It is the fourth time Beijing has called the envoy in during the spat, which began on Tuesday when a Chinese trawler and two Japanese coast guard vessels collided near an island chain in the East China Sea claimed by both sides.
Chinese State Councillor Dai Bingguo urged Japan, through Ambassador Uichiro Niwa, to make a "wise political resolution" and release the trawler and its crew, the Xinhua state news agency said.
"Dai expressed solemnly (to the Japanese ambassador) the Chinese government`s grave concerns and its serious and just position," China`s Foreign Ministry said in a statement quoted by the agency.
Xinhua described Dai as the highest-ranking Chinese official to make a response on the affair.
The move came after China engaged two Japanese survey vessels at sea on Saturday and called off planned talks with Tokyo over the East China Sea in protest at Japan`s handling of the row.
The neighbours had been scheduled to hold discussions later this month on issues relating to the East China Sea.
But Beijing, which has warned Tokyo of a "serious impact" on ties if the trawler and its crew are not released, pushed back the meeting late on Friday.
Accusing Japan of acting "recklessly", it voiced its "strong discontent and grave protest".
"The Japanese side has ignored China`s repeated solemn representations and firm opposition, and obstinately decided to put the Chinese captain under the so-called judiciary procedures," Foreign Ministry spokeswoman Jiang Yu said on Friday.
"Japan`s acts have violated the law of nations and basic international common sense, and are ridiculous, illegal and invalid," she added.
"Japan will reap as it has sown, if it continues to act recklessly."
Tokyo suspects the trawler captain deliberately rammed the two Japanese vessels in a confrontation near the disputed island chain which began on Tuesday morning, and ended after four Japanese patrol boats pursued the Chinese trawler.
The uninhabited islands -- known as Senkaku in Japan and Diaoyu in China -- lie between Japan`s Okinawa island and Taiwan. They are claimed by Tokyo, Beijing and Taipei and are frequently the focus of regional tensions.
On Friday China`s Foreign Minister Yang Jiechi summoned Niwa and stressed Beijing`s determination to "safeguard the sovereignty of the Diaoyu islands", his ministry said.
Territorial disputes in the East China Sea have repeatedly led to strains in Sino-Japanese ties. There are four controversial Chinese gas fields in the sea that Japan says extend into its own exclusive economic zone (EEZ).
The postponed talks were intended to follow on from discussions held in Tokyo in July on plans by Asia`s top two economies to jointly exploit oil and gas fields in the disputed seas.
Jiang said on Thursday that a Chinese "law enforcement" ship had been sent to the area to "protect the safety" of the fishermen working there.
On Saturday, the Japanese coast guard said that ship approached two of its survey vessels and ordered them to cease operations, in an area of the East China Sea which it says falls within its EEZ.
The coast guard said Japan had lodged a complaint through diplomatic channels about the incident, adding that its ships had been able to carry on their work.
The fishing boat`s captain, 41-year-old Zhan Qixiong, was arrested on Wednesday on suspicion of obstructing officers on duty -- a charge that carries a maximum sentence of three years` imprisonment. The crew is also in custody.
A Japanese court on Friday extended Zhan`s detention for up to 10 more days, until September 20. One more 10-day extension can be granted under Japanese law.
Japanese Foreign Minister Katsuya Okada on Friday urged China to handle the issue "calmly and carefully", saying: "We are just acting in accordance with the law."