MANILA - The Philippines accused China on Tuesday of laying concrete blocks on a small group of reefs and rocky outcrops within its territory, the latest escalation in a hostile maritime dispute.
Defence department spokesman Peter Galvez released to the media an aerial photograph of what he said were about 30 blocks on Scarborough Shoal in the South China Sea.
"Boats can be anchored on them. It's hard to speculate what these can be used for, but of course these are concrete blocks that can be used as a foundation for something," Galvez told reporters.
"It's unfortunate that they keep on doing activities that do not contribute to our pursuit towards regional peace."
Galvez said the photograph was taken from Filipino navy aircraft on Saturday, and three Chinese coastguard vessels were also observed there.
AFP could not immediately verify the photograph. When asked for comment, Chinese embassy spokesman Hua Zhang told AFP by email: "I will look into it".
Scarborough Shoal is about 220 kilometres (135 miles) off the main Philippine island of Luzon, within the country's internationally recognised exclusive economic zone.
The outcrop is about 650 kilometres from Hainan island, the nearest major Chinese land mass.
But China claims most of the South China Sea, including waters close to the coasts of the Philippines and other neighbours.
The Philippines and Vietnam have in recent years repeatedly accused China of becoming more aggressive in staking its claims to the disputed area, which are believed to sit atop vast gas and oil reserves.
Diplomatic relations between the Philippines and China, in particular, have become increasingly tense.
The Philippines says China has effectively occupied Scarborough Shoal, home to rich fishing grounds, since last year by stationing vessels there and banning Filipino fishermen.
The Philippines angered China in January this year by asking a United Nations tribunal to rule on the validity of the Chinese claims to most of the South China Sea.
China rejects international arbitration, preferring to deal with the issue on a bilateral basis while maintaining it has sole territorial rights.
In another related flare-up, the Philippine foreign ministry said Tuesday President Benigno Aquino called off a planned trip to China for a trade fair after Chinese authorities imposed conditions on the trip.
Ministry spokesman Raul Hernandez did not disclose the conditions, saying Chinese foreign ministry officials had "advised" the Philippines not to make them public, but signalled they were centred firmly on the territorial row.
"The president stood firm in the defence of the country's national interest," Hernandez said.