China said on Friday it was "strongly dissatisfied" after a U.S. military plane flew over part of the South China Sea near where China is building artificial islands, and called on the United States to stop such action or risk causing an accident.
The Chinese navy issued eight warnings to the U.S. P8-A Poseidon, the U.S. military's most advanced surveillance aircraft, when it conducted the overflights on Wednesday, according to CNN, which had a team on board the U.S. aircraft.
China claims 90 percent of the South China Sea, which is believed to be rich in oil and gas, its claims overlapping with those of Brunei, Malaysia, the Philippines, Vietnam and Taiwan.
Foreign Ministry spokesman Hong Lei said the Chinese military drove away the U.S. aircraft, in accordance with relevant regulations, labeling the U.S. action a security threat to China's islands and reefs.
"Such action is likely to cause an accident, it is very irresponsible and dangerous and detrimental to regional peace and stability. We express our strong dissatisfaction, we urge the U.S. to strictly abide by international law and international rules and refrain from taking any risky and provocative actions," he told a news conference.
"China will continue to closely monitor the relevant area and take the necessary and appropriate measures to prevent harm to the safety of China's islands and reefs as well as any sea and air accidents."
Recent satellite images suggest China has made rapid progress in filling in land in contested territory in the Spratly islands and in building an airstrip suitable for military use and that it may be planning another.
The senior U.S. diplomat for the East Asia, Assistant Secretary of State Daniel Russel, told a media briefing in Washington the U.S. reconnaissance flight was "entirely appropriate" and that U.S. naval forces and military aircraft would "continue to fully exercise" the right to operate in international waters and airspace.
On Thursday, U.S. Deputy Secretary of State Antony Blinken said China's land reclamation in the South China Sea was undermining freedom and stability and risked provoking tension that could lead to conflict.
The Global Times, a tabloid owned by the ruling Communist Party's People's Daily, called the U.S. overflights "provocative".
"Washington is purposefully raising tensions with China, a move that has created a higher risk of a physical confrontation," the newspaper said in an editorial on Friday.
"China should be prepared to ramp up its countermeasures, one notch at a time, according to the degree of provocations from the U.S."