A Philippine military aircraft confirmed Saturday that a Chinese naval frigate remains stranded in disputed waters of the South China Sea, a military spokesman said.

The Chinese frigate and smaller craft were sighted by a Philippine Islander plane, said regional military spokesman Colonel Neil Anthony Estrella.

"During the aerial reconnaissance mission, they were able to confirm, based on photographs, that there is indeed a ship with bow number 560 aground at Half Moon Shoal," he told AFP.

He said five more vessels and a number of smaller boats were assisting the grounded ship.

A navy ship and a coast guard vessel had been dispatched to the area to monitor the Chinese operations, he added.

He stressed that the shoal was just 60 nautical miles from the western Philippine island of Palawan, well within the country's 200-nautical-mile exclusive economic zone, as recognised by international law.

Foreign Department spokesman Raul Hernandez said in a statement, "we need to find out what really happened with the Chinese frigate in our territory".

He reiterated that the Philippines would provide assistance to move the ship if China requested it.

The Chinese government earlier confirmed that the ship was on "routine patrol" when it became stranded near Half Moon Shoal in the Spratly Islands on Wednesday evening.

The stranding highlights the territorial conflicts between the two countries which marred the ASEAN Regional Forum in Cambodia this week.

At the forum, the Philippines' foreign minister denounced Chinese "duplicity" and "intimidation" in the South China Sea and conflicting positions on the issue prevented the Association of Southeast Asian Nations from issuing its customary joint statement.

The Philippines and China have been in a standoff since Chinese ships blocked the Philippine navy from arresting Chinese fishermen at the disputed Scarborough Shoal in the South China Sea in April.

The Philippines says the shoal is also within its EEZ but China claims the entire South China Sea as its historical territory, even up to the coasts of other Southeast Asian countries. The sea is believed to sit atop vast oil and gas deposits.

In Manila, a group of Filipino-Americans on Saturday called for a boycott of Chinese products and a day of prayer to rally support against China's actions.