Two Chinese diplomats have been flown to China to stand trial for a gun attack in the Philippines that killed two of their colleagues and wounded another, Philippine authorities say.

China's consul-general in the central city of Cebu survived after being shot in the neck, but two of his staff members died during the lunchtime attack at a restaurant on Wednesday.

"They (the suspects) already left last night, direct flight from Cebu to Xiamen," Philippines foreign ministry spokesman Charles Jose said in a text message, referring to a south-eastern Chinese city.

"Yes, they will be prosecuted in China," he added.

The motive of the gun attack was not known, and the positions held by the two suspects at the consulate remained unclear.

China has the death penalty, while the Philippines does not.

Mr Jose said that "the Chinese government would like to take custody of them, and they will have to undergo the Chinese legal process."

The Chinese foreign ministry has given little information about the attack. Chinese embassy spokeswoman Li Lingxiao said she had no comment to make on the Philippine government's announcement over the transfer of custody.

Staff at the upmarket Cebu restaurant earlier said the victims and suspects were among nine Chinese diners who had gathered to celebrate the birthday of the consul-general, Song Ronghua.

The Chinese embassy in Manila later described the couple as accredited Chinese diplomats and invoked diplomatic immunity, Mr Jose said, to escape Philippine laws and instead face charges in China.

Cebu provincial police chief Superintendent Tom Banas said police handed the suspects over to the Philippines foreign ministry on Friday night.

"I was informed they have already been flown out to China," Mr Banas added.

AFP