MANILA - Three Chinese nationals and one Filipino were arrested Friday and about 20 kilos of "ice" seized in a major anti-narcotics raid outside Manila, the Philippines police said.

The four suspects were believed to have been selling illegal drugs in greater Manila, the police said in a statement.

The operation at the suspects' hideout was carried out with the cooperation of anti-narcotics units from the United States and China, it added.v A Philippine government anti-drugs agency estimates that there are about 6.7 million drug users in the country, mostly hooked on amphetamines and marijuana.