The Philippines says it has filed a diplomatic protest over the presence of more than 270 Chinese vessels near a Philippine-occupied island in the disputed South China Sea.

Presidential spokesman Salvador Panelo told a news conference on Monday that the Philippines’ Department of Foreign Affairs (DFA) had protested the presence of 275 Chinese boats spotted by the military near Thitu Island.

China has said the vessels are fishing boats.

“The mere fact that they are there and just staying there for a week, why, what are they doing there?” Panelo said, without providing details of when and where the protest had been filed.

Data provided by the Philippine military showed it had spotted 275 Chinese boats near Thitu between January and March this year.

Zhao Jianhua, China’s ambassador to the Philippines said they were fishing boats and denied media reports that the fishermen were carrying guns. He said both Chinese and Filipino fishermen were present in the disputed waters.

Zhao also dismissed concerns about a potential armed conflict in the sea.

“We have been handling this issue [with the Philippines] through friendly diplomatic channels, so you don’t need to worry about whether there will be any kind of outbreak of conflict,” the Chinese diplomat said.

Meanwhile, the Philippines and the United States kicked off an annual joint military drill — involving roughly 7,500 troops — on Monday.

A Philippine military official, Lieutenant General Gilbert Gapay, told reporters that the exercises were aimed at enhancing natural disasters response and “not directed to any threat or existing security concern,” an apparent reference to China.

China and the Philippines have competing claims over territory in the South China Sea, through which five trillion dollars in shipping trade passes annually. There are also claims by Vietnam, Malaysia, Indonesia, Taiwan, and Brunei.

Last month, US Secretary of State Mike Pompeo said the US would come to the Philippines’ defense in the event of a confrontation with China.

US vows military support for Philippines in war with China

Secretary of State Mike Pompeo says the US will support the Philippines in the event of a military confrontation in the South China Sea.

The US is allied to the Philippines by treaty.

But Philippine President Rodrigo Duterte, who took power in 2016, has been more inclined toward China. Under his presidency, the territorial dispute with Beijing has been less emphasized.

Duterte, who has sought Chinese investment in his country, famously unleashed several diatribes against former US president Barack Obama and partially downgraded military ties with America.