MANILA - The Philippines' national security adviser called on Friday for Chinese diplomats to be expelled over an alleged leak of a phone conversation with a Filipino admiral in a significant escalation of a bitter row over the South China Sea.

China's embassy in Manila had orchestrated "repeated acts of engaging and dissemination of disinformation, misinformation and malinformation", with the objective of sowing discord, division and disunity, Eduardo Ano said in a statement.

Those actions "should not be allowed to pass unsanctioned without serious penalty", he said.

Chinese foreign ministry spokesperson Lin Jian called the comments provocative and said Chinese diplomats in the Philippines had to be allowed to do their job.

"China solemnly requests the Philippine side to effectively safeguard the normal performance of duties by Chinese diplomatic personnel, stop infringing and provoking, and refrain from denying the facts," Lin said at a regular press briefing in Beijing.

The office of Philippine President Ferdinand Marcos Jr and the foreign ministry did not immediately respond to requests for comment.

The two countries have been embroiled in a series of heated stand-offs this past year in disputed areas of the South China Sea as the Philippines, emboldened by support from the United States and other allies, steps up activities in waters occupied by China's vast coast guard.

Asked to comment on the latest row, a spokesperson for the U.S. State Department said: "We are aware of the media reports and defer to the Philippine Department of Foreign Affairs."

China has accused the Philippines of trespassing and of treachery, while Manila has scolded Beijing for what it says is a policy of aggression and dangerous manoeuvring inside its exclusive economic zone.

The expelling of diplomats could intensify a row that has so far seen heated exchanges, diplomatic protests and the ramming and water-cannoning of Philippine ships at two disputed shoals, the closest of which is more than 850 km (530 miles) away from mainland China.

Ano was referring to a news report this week of an alleged leak of a call between a Chinese diplomat and a Filipino admiral discussing a dispute over the South China Sea, which carried a transcript that showed the admiral agreeing to concessions with China.

According to the transcript published by the Manila Times, the admiral agreed to China's proposal of a "new model", where the Philippines would use fewer vessels in resupply trips to marines stationed at a grounded warship at the disputed Second Thomas Shoal, and notify Beijing about the missions in advance.

Reuters has not heard the reported phone conversation and could not verify the contents of the published transcript. The report said the conversation had taken place in January and the transcript was provided by a "ranking Chinese official", which it did not name.

'INTERFERENCE OPERATIONS'

Ano said he backed the defence minister's call for the foreign ministry to take appropriate action against embassy officials, who he claimed recorded an alleged phone conversation in violation of Philippine laws, including its anti-wire tapping act, as well as serious breaches of diplomatic protocols.

"Those individuals in the Chinese embassy ... and those responsible for these malign influence and interference operations must be removed from the country immediately," he said.

On Wednesday, Chinese spokesperson Lin said the embassy in Manila had released details about "relevant communications" between the two countries on managing the situation at the Second Thomas Shoal.

Lin, in comments shared by the embassy, did not elaborate on what details or communications were released, or when, but said "facts are clear and backed by hard evidence that cannot be denied".

"The Philippines has insisted on denying these objective facts and seeks to mislead the international community," Lin added.

China has long been vexed by the Philippines' maintaining its small military presence aboard the grounded warship Sierre Madre at the Second Thomas Shoal, where it has been since 1999 to try to prop up its territorial claim.

Beijing has repeatedly said the Philippines had agreed to tow that ship away, which Manila denies.

Manila-based political analyst Julio Amador said expelling diplomats should be part of the Philippines' diplomatic tool kit and Chinese embassy officials had shown they did not value their working relationships with Filipino officials.

"Diplomacy is based on trust, yet China is trying to make it look like all meetings between its diplomats and Philippine government representatives are negotiations with binding results," he said.

"It has no right to make demands on the Philippines on how the latter manages areas over which it has sovereign rights."

(Additional reporting by Joe Cash and David Brunnstrom; Writing by Martin Petty; Editing by Neil Fullick and Raju Gopalakrishnan)