2014 (AFP) - A Philippine re-supply ship evaded a Chinese coastguard blockade in the South China Sea Saturday to reach Filipino soldiers based on a remote reef claimed by both countries, the military said.

The dramatic, two-hour stand-off witnessed by AFP was the latest in a rapid-fire series of escalations in a dispute between the two countries over their competing claims to waters and islands close to Philippine landmass.

Saturday's incident took place at Second Thomas Shoal, where a small number of Filipino soldiers are stationed on a Navy vessel that was grounded there in 1999 to assert the Philippines' sovereignty.

The Philippine military said the ship, a fishing vessel with soldiers on board, completed its mission to deliver fresh supplies to the navy ship and rotate the troops.

"They were able to pass through. The Chinese coastguard vessel and the mission is a success," Cherryl Tindog, a spokeswoman for the military's western command, told AFP.

"We have successfully re-supplied and rotated the troops."

An AFP reporter and photographer recorded the two-hour confrontation above calm turquoise waters while on board a Philippine military plane that circled above the area throughout.

Four Chinese vessels had encircled Second Thomas Shoal as the Philippine vessel approached, according to the AFP reporter.

Two of the vessels, with a "Chinese Coast Guard" written on the hulls, then chased the Philippine boat and tried to block it from reaching the shoal.

The vessels appeared to get within a few hundred metres of each other, with one of the Chinese vessels sailing across the Filipino vessel's bow twice.

The supply vessel later managed to reach shallow waters around the shoal, where the Chinese ships, with much-larger displacements, could not follow without the risk of running aground.

During the confrontation, the Chinese vessels radioed the Philippine boat and demanded that it leave the "Chinese territory", local television stations reported, citing their journalists on board the Filipino boat.

The Philippines foreign affairs department denounced the Chinese coastguard action.

"We condemn the harassment by the Chinese coastguard of our civilian vessels which are on their way to Ayungin Shoal to resupply provisions to our personnel stationed there," it said in a statement, using the Filipino name for the outcrop.

"We demand that China cease taking actions that are a threat to our security."

The statement stressed that the Philippines had "sovereign rights and jurisdiction over" Second Thomas Shoal, insisting it was part of the country's continental shelf.

Calls by AFP to the Chinese embassy in Manila and its spokesman went unreturned Saturday.

But China has repeatedly said it has sovereign rights over Second Thomas Shoal and the Philippines was illegally "occupying" it.

China claims most of the South China Sea, even waters and islets approaching its neighbours.

Second Thomas Shoal is part of the Spratlys, a chain of islets and reefs that sit near key shipping lanes, are surrounded by rich fishing grounds and are also believed to lie atop huge oil and gas reserves.

They are around 200 kilometres (125 miles) from the western Philippine island of Palawan and about 1,100 kilometres from the nearest major Chinese land mass.

The Philippines grounded an old Navy ship, the BRP Sierra Madre, at Second Thomas Shoal in 1999, four years after China built structures on nearby, Filipino-claimed Mischief Reef.

Filipino troops have kept a presence on the ship ever since.

However, until this month, China had never sought to block the Philippines from re-supplying or rotating its soldiers there.

China successfully turned away a Philippine re-supply boat on March 9, forcing the Philippine military to airdrop supplies to the unit.

Saturday's mission was the next attempt to reach the shoal.

Although the military does not release figures on the number of soldiers stationed at Second Thomas Shoal, there are believed to be fewer than 10.

Saturday's confrontation occurred a day before the Philippines was due to file its case with a United Nations tribunal to challenge China's territorial claim to most of the South China Sea.

The Philippines' legal case has infuriated China, which has said it will not participate. China has also warned the Philippines that bilateral relations will suffer if it continues to pursue its appeal to the United Nations.