China has fired two missiles into the South China Sea, amid tensions between Beijing and the United States over the disputed waters, South China Morning Post reported on Thursday.

The DF-26B and DF-21D missiles were fired on Wednesday and targeted an area between the southern island province of Hainan and the Paracel Islands, the newspaper cited unidentified officials as saying. The DF-26B was launched from the northwestern province of Qinghai while the DF-21D was fired from Zhejiang province south of Shanghai on the east coast.

This came after a US spy plane reportedly entered a Chinese-designated “no-fly zone” in an area where live-fire naval drills were taking place. China described the flight in the area as a “provocative action”.

The DF-26B missile, which was formally launched earlier this month, is dubbed an “aircraft-carrier killer” as it is capable of hitting moving targets at sea. Chinese defence ministry spokesperson, Senior Colonel Wu Qian has said that the missile can carry conventional or nuclear warheads and is capable of launching precision strikes on land and sea targets, according to Al Jazeera.

The dispute over control of the South China Sea has been a source of tension between the United States and China, as well as between Beijing and its neighbouring countries.

The United States accuses China of militarising the sea, which is one of the busiest trade routes of the world, and trying to intimidate other Asian countries, who might want to exploit its extensive oil and gas reserves, according to Reuters. US warships have gone through the area to assert the freedom of access to international waterways.

China in return, has deployed troops, aircraft, radar and missiles stations on some of the seven man-made islands of the South China Sea, allowing the country to expand its military reach beyond its shores, according to AP.

‘Threat to peace and security,’ says US

The United States Department of Defense in statement on Thursday said that the Chinese test launches of ballistic missiles in the South China Sea were a threat to peace and security in the region. The Pentagon said the move was against the country’s 2002 commitment to avoid provocative activities in the disputed seas.

“Conducting military exercises over disputed territory in the South China Sea is counterproductive to easing tensions and maintaining stability,” the Pentagon said. “The PRC [People’s Republic of China] ’s actions, including missile tests, further destabilize the situation in the South China Sea.”

US said the Chinese military’s actions were “the latest in a long string of PRC actions to assert unlawful maritime claims and disadvantage its Southeast Asian neighbors”.

“The PRC’s actions stand in contrast to its pledge to not militarize the South China Sea and are in contrast to the United States’ vision of a free and open Indo-Pacific region, in which all nations, large and small, are secure in their sovereignty, free from coercion, and able to pursue economic growth consistent with accepted international rules and norms,” the statement added.