Guangdong police seized more than 700 kilograms of methamphetamine and arrested 28 suspects - more than half of them from Taiwan - in a joint operation with authorities from Fujian province and Taiwan aimed at drug smuggling.

The suspects used a fake courier company in Dongguan as a cover for storing the drugs. They had planned to smuggle the drugs to the Philippines by sea but failed, the police said. The smugglers then used cars to transfer the drugs from ports to the company, where they were caught on Feb 28.

A suspect drove a car to the company, but instead of parking it outside, as on previous occasions, the suspect parked it inside the company warehouse.

"After more than a month of investigation, and based on our judgment, we believed that the car carried drugs, so we carried out the operation immediately," a Guangdong official who participated in the raid said. He asked not to be named.

Nine guns, 1.5 million yuan ($230,000), HK$2 million ($258,000) in cash and several bank cards, as well as 11 cars were also seized in the operation.

It was the biggest drug-related operation to be foiled by the Guangdong border-control department this year.

"Drug smuggling in Guangdong province has been curbed to a large degree this year, but it still remains active," Deng Jianwei, director of drug enforcement at the Guangdong Department of Public Security, told reporters at a news conference in Dongguan on Thursday. "The anti-drug situation in the province is still serious. We have to remain vigilant."

Overseas demand for drugs has fueled illegal activity in the province, which has often been used as a base to transport drugs overseas, Deng added.

In the first quarter of this year, 3,433 suspected drug smugglers were apprehended and 4.83 metric tons of drugs were seized by Guangdong authorities, Deng said. The authorities also broke up 23 drugmaking factories and detained 26,812 drug users.

According to the Guangdong official, the courier company used in the recent case was not really engaged in the delivery business but only served as a meeting place for the suspects.

The smugglers intended to store the drugs temporarily at the fake company and transport them to overseas markets when they found an opportunity, the official said.

It is not known where the drugs were made. An investigation is ongoing.

Deng said identifying drug smugglers in Guangdong is more complicated than in other areas because many of them have international backgrounds and are engaged in cross-border business.

Last year, more than 500 drug smugglers from more than 40 countries and regions were arrested in the province. Of those, 252 came from Hong Kong and about 70 from Taiwan.

Last month, an international drug trafficking operation controlled by Hong Kong residents was broken up by Guangdong police. About 400 kilograms of cocaine from South America was confiscated.