The Chinese Embassy in Pyongyang asked North Koreans to ensure the safety of the detained fishermen, Chinese diplomat Jiang Yaxian told the official Chinese Xinhua News Agency.
China's Global Times reported 16 Chinese fishermen were kidnapped May 5 by armed North Koreans. The report, quoting analysts, said the Chinese government should take a tougher stance toward Pyongyang to firmly ensure the safety of its citizens.
Xinhua, quoting Jiang, said a private fishing boat from Dalian City in northeast China's Liaoning province was captured by North Koreans. Jiang said the boat's owner Yu Xuejun called the Chinese Embassy May 10 about the incident.
"Upon receiving the call, the Chinese Embassy promptly made representations to the bureau of consular affairs of the DPRK Foreign Ministry, asking the DPRK side to release the boat and the fishermen as soon as possible," Jiang said.
The Democratic People's Republic of Korea -- DPRK -- is the official name of North Korea.
The boat owner Yu was quoted as telling Global Times he has received eight calls demanding about $100,000 as ransom before Sunday noon. He stressed the vessel was in Chinese waters when the incident occurred.
"The ship was equipped with GPS and Beidou positioning systems to make sure our fishermen know their accurate location every second," Yun told the Global Times. He said the Liaoning provincial fishery authority can also monitor all fishing activities.
Yu told the newspaper the abductors expertly removed the positioning systems and confiscated communication devices after boarding the boat.
Yu said there have been no calls from the North Korean side since the deadline passed.
"I can't afford the ransom as required. What worries me most is the personal safety of the 16 crew members," said Yu.
China remains the closest ally of North Korea, which faces tough sanctions imposed by the U.N. Security Council for its Feb. 12 nuclear test, its third since 2006. The test was widely condemned by the international community, including China.
Cui Zhiying at Shanghai's Tongji University told the Global Times relations between China and North Korea are gradually changing from traditional ideological allies to normal bilateral relations. As a result, such incidents as the boat seizure are being disclosed more frequently.
Jin Qiangyi, director of Asian Studies Center at Yanbian University, said China in the past has been inclined to deal with such disputes in a low-key manner and North Korea has taken advantage of the policy.
"It's also possible that the nuclear state is taking revenge on China after the U.N. imposed a series of sanctions on it following its third nuclear test," said Jin He asked the Chinese government to be firm about the safety of its citizens, otherwise, such incidents would only recur.