Updated

Thai police said Monday they have seized more than 1 million methamphetamine tablets this month, as trade in the illicit drug shows little sign of abating.

The Narcotic Suppression Bureau displayed 1.21 million methamphetamine tablets and 17 kilograms (37.4 pounds) of crystal methamphetamine it seized as it made arrests in four separate cases.

The biggest seizure came last Thursday at a police checkpoint in Prachuap Khiri Khan province, about 240 kilometers (150 miles) south of Bangkok. Police said the arrested men admitted transporting 910,000 tablets destined for the southern Thai provinces of Songklha and Hat Yai.

Other drug seizures took place at a mall in Bangkok and in the provinces of Lampang and Chiang Rai in Thailand's north, which borders Myanmar, where most methamphetamine seized in Thailand originates.

Thailand has struggled for almost two decades against a tide of methamphetamine fueling crime and addiction on a huge scale. In 2003, then Prime Minister Thaksin Shinawatra launched a "War on Drugs" that led to an estimated 2,800 extrajudicial killings for which he was criticized by human rights advocates.

Thai authorities usually make several methamphetamine seizures a year of a million or more tablets, but the drug continues to enter from areas of Myanmar over which its government has little control, and via Laos. In a high-profile case in January, Thai police arrested a Laotian man they described as a major drug kingpin with alleged ties to Thai celebrities.