China on Wednesday urged the Philippines to "immediately" release detained fishermen and the boat, state-run Xinhua News Agency reported. China has demanded the Philippines "make rational explanations," Foreign Ministry spokeswoman Hua Chunying told a press briefing, warning the Philippine side to take no more provocative action. Chinese maritime police boat has arrived at the sea area. The ministry and the Chinese Embassy in the Philippines have already lodged representations with the Philippine side. Hua reiterated that China has undisputable sovereign rights over the sea area, including the Half Moon Shoal of Nansha (Spratly) Islands, where the incident occurred. "China always urges Chinese fishermen to conduct fishing activities in accordance with the law," she said, urging relevant countries to properly handle relevant affairs and safeguard the legitimate rights of Chinese fishermen. Earlier media report said that 11 Chinese fishermen aboard fishing boat Qiongqionghai 09063 were seized by the Philippine police at about 10 a.m. in waters off the Half Moon Shoal. Several armed men forced themselves onto the boat and fired four or five shots in the air, the report said, adding that they took control of the boat. Both China and Philippines insist sovereignty over the oil-rich Spratly Islands chains. The Spratly Islands are also claimed by Taiwan, Brunei, Malaysia and Vietnam. Tensions between China, which claims almost the entire South China Sea, and neighboring countries over territorial claims to the South China Sea and its island groups have escalated in recent years