BEIJING, June 22 (Reuters) - Armed gangs are bringing drugs into China in growing numbers, with farmers moving to cities for work becoming a new target, a top narcotics official said on Thursday, describing the overall situation as "not optimistic".

China had nearly 800,000 drugs addicts last year, 30 percent of whom were farmers, and most Chinese addicts are hooked on heroin, with ecstasy and amphetamines also popular, said Chen Cunyi, deputy head of the National Narcotics Control Commission.

"There are farmers who come to the city as migrant workers, and they see their friends having fun in entertainment places, who introduce drugs to them and they're curious so they try it," Chen said.

"They take ecstasy or other drugs with their friends, and it's easy to get hooked," he told reporters on the sidelines of a news conference.

"The international problem of drug abuse is enveloping yet more countries, and the sources, types, production and number of addicts of drugs is rising," said Chen. "Under this influence, China's fight against drugs is not optimistic."

With most drugs coming in from Afghanistan and Golden Triangle countries like Laos and Myanmar, gangs were taking up arms to defend themselves, Chen said.

"In border regions where drugs are sold, it's easy to buy guns from outside the country," he added. "Every year weapons are becoming more prominent in drugs cases that we bust."

State media has said China has been stepping up border checks, particularly on the frontier with Myanmar, a country where ethnic insurgents have been fighting the Yangon government for decades, and often using drugs to finance their wars.

But Chen added that China was having some success in what the government terms a "national people's war on illicit drugs".

Last year China arrested nearly 60,000 people in connection with drugs cases and seized 17.5 tonnes of narcotics, Chen said, giving no comparative figures.

Many drug runners had stopped using China as a manufacturing base, the official added, and shifted operations to surrounding countries.

"They have discovered that the risk from drug control activities is getting greater and greater, and it's very easy to be found out, so some have moved overseas and are cooperating with foreign gangs, opening factories there," Chen said.