Customs officers in Yunnan province confiscated more than 56 kilograms of illegal drugs as they thwarted three attempts to smuggle drugs across the border in the last four months, authorities said on Wednesday.

Nine suspects were arrested, said the authorities.

The suspects were allegedly trying to smuggle methamphetamine, a synthetic drug, across the Chinese border from Myanmar before they were caught by the officers, customs in Kunming, capital of Yunnan, said in a statement.

Customs officers in Ruili, a subbranch of Kunming, first received a tip-off from an informant in August that a group of drug dealers would try to smuggle a large amount of synthetic drugs into China from Myanmar, the statement said.

The group's first attempt was stopped by customs officers on Aug 30 when they caught a suspect on a motorcycle who was allegedly trying to smuggle almost 16 kg of methamphetamine in the Menglian Dai, Lahu and Va autonomous county, which borders Myanmar.

The officers went on to thwart another two attempts on Sept 4 and Sept 9 in Menghai and Yunxian counties as they captured another eight suspects and confiscated close to 40 kg of methamphetamine.

"In one case, five drug traffickers disguised as tourists to Myanmar, and it would never occur to you that they were drug dealers at a first look. They even provided exactly the same testimonies during their interrogations," said Chen Weisi, an officer with the Ruili Customs who was part of the special enforcement team on the case.

The drug dealers also adapted trucks and cars for the smuggling operation, he said.

The officers had to travel between the five cities that border Myanmar as the drug dealers chose three different trafficking routes, he said.

As a province that is located closely to the Golden Triangle area, which includes Myanmar, Laos and Thailand, Yunnan is a transfer point and a market for drug dealers overseas, Chen said.

Synthetic drugs, especially methamphetamine, have replaced heroin as the major drug for the dealers, he said.

Last year, an estimated 463,000 people started using illegal drugs, and 80 percent of them chose synthetic drugs, including meth, according to the Ministry of Public Security.

The economy loses 500 billion yuan ($82 billion) a year through such abuse, the ministry has estimated.