China has seized a tiny sandbank in the South China Sea as tensions continue to grow in the region. Chinese state broadcaster CCTV released images of four officers standing on the disputed reef of Sandy Cay in the Spratly Islands.

The officers can be seen wearing all black and holding the Chinese flag. CCTV said China had "implemented maritime control and exercised sovereign jurisdiction" on the 200 sq metre reef earlier this month. The move comes as China's regional dispute with the Philippines continues to escalate, with both nations staking claims on various islands.

The Philippines released a picture on Sunday of officers holiding up their flag as they mimicked Beijing's photo. However, as reported by the BBC, it is unclear whether the picture was also taken at Sandy Cay.

The National Task Force West Philippine Sea (NTF-WPS) also issued a statement which said it witnessed "the illegal presence" of a Chinese Coastguard vessel 1,000 yards (914 metres) from one of the sandbanks. They also reportedly saw seven Chinese militia vessels.

The statement said: "This operation reflects the unwavering dedication and commitment of the Philippine Government to uphold the country's sovereignty, sovereign rights and jurisdiction in the West Philippine Sea."

Sandy Bay is located near a Philippine military outpost on Thitu Island. It is reportedly used by Manila to track Chinese movements in the area.

While the White House said claims China has seized the reef were "deeply concerning if true", there is no sign that Beijing is permanetly occupying the island. The Chinese coastguard has reportedly now left the area.

Meanwhile, James Hewitt, US National Security Council spokesperson, said that "actions like these threaten regional stability and violate international law". He added that the White House was "consulting closely with our own partners".

China has recently criticised the US and Philippine forces as they continue to carry out the Balikatan exercises. Beijing has described the annual war scenario drills, which are set to involve up to 17,000 personnel in the coming days, as provocative.

The US Marine Air Defense Integrated System also fired missiles off the coast of the northern Philippines on Sunday. The US anti-ship missile system NMESIS will also feature in the drills.

According to the Philippines military, the drills are a rehearsal for nation defence. Third Marine Littoral Regiment Officer John Lehane said: "This type of training is absolutely invaluable to us."