The Philippine government on Wednesday released what it says are surveillance pictures of Chinese coast guard ships and barges at a disputed shoal in the South China Sea, in an apparent diplomatic gambit to publicize its concerns at a regional summit being attended by China's premier and Southeast Asian leaders.

Philippine President Rodrigo Duterte plans to ask Premier Li Keqiang at the summit in the Laotian capital whether the vessels were on another island-making mission on the Scarborough Shoal. China has built seven such islands in the disputed, resource-rich sea, alarming neighbors and rival claimants.

Chinese Foreign Ministry spokeswoman Hua Chunying said that China hadn't done anything to alter the circumstances in the waters surrounding the shoal.

"What I can tell you is that the situation in waters near Huangyan Island remains unchanged and China hasn't made any new moves," Hua said in Beijing, using the shoal's Chinese name. "We should be highly alert against the mischief-making intentions of people who spread such groundless information in such situations."

Asked how disturbed the Philippines was by the presence of the Chinese ships, Duterte's spokesman Ernesto Abella told a news conference: "Enough to announce it."

He said that China and the Philippines were discussing the issue, but gave no details.

"There are talks at this stage," Abella said. He refused to comment if the Philippine policy was to prevent any country from constructing at or transforming Scarborough, a coral reef, into an island.

If the Chinese government confirms the photos, the Philippines will lodge an official protest, said Philippine Defense Secretary Delfin Lorenzana.

Duterte has taken a more reconciliatory track to rebuild relations with China ad has said he would not raise the long-simmering territorial disputes in an adversarial manner that might upset Beijing.

Relations were severely strained under Duterte's predecessor because of the conflict.

However, Duterte expressed alarm after a Philippine surveillance plane recently spotted four Chinese coast guard ships, four suspected barges, including one equipped with what appeared to be a crane. The government released the photos with a diagram showing the vessels' exact locations at the shoal, which the Chinese coast guard seized after a tense standoff with Philippine vessels in 2012.

Hours after the Philippines released the pictures, the Association of Southeast Asian Nations met with Li and his aides. The South China Sea dispute was tackled at the closed-door meeting with some of the leaders, including Duterte, who reiterated calls for the conflicts to be resolved peacefully and in accordance with international law, Communications Secretary Martin Andanar said.

He quoted the Chinese premier as saying that there was now a "positive direction" in Beijing's relations with ASEAN and that the disputes should not affect overall relations.

The U.S. military has also expressed concerns over the possibility that China might turn Scarborough into another island, something that would give Beijing's forces control over a swath of the South China Sea used as a passageway to the Taiwan Strait.

China claims virtually the entire South China Sea as its own, citing historical reasons. It has rejected a July 12 international arbitration ruling that called its claims illegal. The tribunal ruling also rebuked China for its land reclamation activities.