Thai officials have stepped up security along their borders because of fears that substantial stockpiles of illicit drugs await in neighboring countries for transport to the kingdom.

“We estimate that five million narcotic pills have been stored in neighboring countries and are ready to be carried into Thailand,” said Kitti Limchaikij, the secretary-general of Thailand’s Narcotics Control Board, on Wednesday.

He added that there are significant problems with drugs being stored in areas populated by ethnic minority groups, which make it difficult for Thai officials to investigate.

“There have been several battles between security forces and traffickers because the cost of drugs has increased, so traffickers work harder to protect their stock by hiring armed groups,” Kitti said.

The drug problem does not only affect the Thai-Burmese border area—traditionally a main conduit for drugs into Thailand. Traffickers have been confronted in increasing numbers recently along the Thai borders with Cambodia and Laos. 

Pol Gen Wongkot Maneerin, the deputy chief of the Thai Royal Police, said that the increase in trafficked drugs into Thailand corresponds with a higher incidence of drug use throughout the country.

Meanwhile, officials in the Mae Sot district of Tak Province, near the border with eastern Burma, have also stepped up security efforts to stop drugs from crossing the border from Burma’s Karen State.

Seri Thaijongrak, head of the Mae Sot Customs Office, said that the office has increased its efforts to suppress illicit drugs and arrest traffickers along the Burmese border. Those efforts followed reports of an increase in drug use in the area, according to a report in the Thai language newspaper Manager on Thursday.

Arrests of drug traffickers have increased in recent weeks in Bangkok—a major market for drugs coming across Thailand’s borders.

Bangkok police on Wednesday arrested two men—Maitree Atthawuttichai and Mongkol Jaioakdee—who were in possession of three kilos of “yaa ice,” a type of methamphetamine, in Nonsee district. The drugs had a street value of 9 million baht (more than US $250,000).

Pol Lt-Gen Suwat Chanittikul, chief of Thailand’s Narcotics Suppression Bureau, said that an investigation found that Maitree was a member of a major drug trafficking group and was responsible for procuring chemicals and equipment for drug production in a factory across the border in Burma, from which he received supplies for distribution in bars and clubs in Bangkok.