Dangerous movements in China and a cat-and-mouse maritime chase in the Philippines

​The BBC witnessed a Chinese Coast Guard ship block a Philippine patrol vessel in the South China Sea, causing a near collision in waters where Beijing's vast claims have alarmed the US and its allies. This was the day after President Ferdinand Marcos Jr met Chinese Foreign Minister Qin Gang in Manila, and expressed hope for open communication lines on the South China Sea dispute. China claims almost the entire South China Sea, including the Spratlys, which is also claimed in part by the Philippines. This has turned the South China Sea into one of the world's biggest flashpoints, as access to these waters is key to defending Taiwan and hosting $5tn (£4tn) of global trade every year. China has ignored an international arbitration court's ruling that its claim to almost the entire South China Sea is ill-founded, and has instead built artificial islands over reefs, heightened patrols, and more recently, shone lasers at Philippine ships to obstruct their view. The Philippines has leaned on its long-standing ally, the US, which brands China's moves as disruptive of other countries' "freedom of navigation". China made "highly dangerous manoeuvres" at Second Thomas Shoal and Filipino officials were well within their authority to patrol the area. Beijing accused the Philippines of intrusion into Chinese waters. At dawn on 23 April, the Filipino crew noticed how the Chinese ship that had been shadowing their vessel increased speed, as shown by the thick black smoke from its exhaust. The BBC witnessed the high seas chase playing out on relatively calm turquoise waters from a second Philippine ship, the Malabrigo, roughly one kilometre away. Eventually the Chinese ship caught up with the Philippine boat, and it became clear that the latter could not outmanoeuvre a vessel more than twice its size. The Chinese ship blocked the way and refused to budge, forcing the Malapascua to turn off its engine to avoid a collision. The Chinese ship came as close as 45m (146ft) to the Malapascua's bow due to the "sudden and really very dangerous manoeuvre". The Philippine Coast Guard vessel was involved in a near-collision with the Chinese in the South China Sea, which was the closest near-collision for the vessel. After a 30-minute stand-off, the Philippine ships turned away and were unable to patrol the Second Thomas Shoal, one of the few disputed outcrops and islands that Manila occupies. China's routine blocking of Filipino patrols and supply missions to the Second Thomas Shoal was part of the case brought before the Permanent Court of Arbitration in 2016. In recent weeks, some Chinese ships have refused to respond to warnings from Filipinos, in an apparent new tactic. The coastguard mission also found some 100 militia ships near V-shaped Whitsun Reef, in the Spratlys' coral region. The BBC's Virma Simonette was among a group of journalists on board the Philippine Coast Guard vessel on a week-long patrol in the South China Sea.​