Manila -- Philippine and Chinese narcotics agents raided a clandestine drug laboratory and seized 1.5 billion pesos (US$30.3 million) worth of illegal methamphetamine, dealing a big blow to one of the biggest drug syndicates in Asia, an official said Saturday.

The raid Friday came three days after three suspected members of a Chinese drug syndicate were nabbed at Manila airport as they were about to leave the country, said Dionisio Santiago, chairman of the Philippine Drug Enforcement Agency.

The three Chinese led officers to the laboratory, but police were unable to get a warrant to search the premises until Friday, Santiago said. Police also arrested two Filipinos working at the laboratory, he said.

The anti-drug operations were made in coordination with agents from China's National Narcotics Control Commission, which had arrested 13 other members of the China-based syndicate three weeks earlier, Santiago said.

The drug laboratory, set up in a house in Calumpit town in Bulacan province north of Manila, yielded 30 kilograms (66 pounds) of methamphetamine hydrochloride, popularly known as shabu in the Philippines, and 200 kilograms (440 pounds) of semi-processed methamphetamine.

In 2004, authorities seized 1.3 billion pesos (US$26.3) of shabu and other chemicals from another illegal drug laboratory in central Mandaue city. Both laboratories were operated by the Shao Chuntian drug ring, Santiago said.

Santiago said the arrest of the 13 in China was part of a sting operation by Chinese authorities that resulted in the seizure of a ton of ephedrine, which could produce 600 kilograms (1,320 pounds) of methamphetamine.

"We believe that the Chinese government is really sincere in its effort to stop the massive production of amphetamines and other illegal drugs in their country. This is the reason why we are getting full cooperation from them," he said.

He said the three men arrested at the Manila airport were shabu "cooks" sent by the syndicate from China, and burn marks on their faces, hands and bodies indicated they were in close contact with chemicals used in shabu production.

He said the men, who will be deported to China where they may face the death penalty, learned to speak English and Filipino in Manila.

President Gloria Macapagal Arroyo praised the cooperation between the Filipino and Chinese anti-narcotics agencies.

"Let us continue to work together," she said.