Jordanian authorities have seized a quarter of a million Captagon pills buried near the Syrian border in the north of the kingdom.
A police anti-narcotics unit received intelligence that the illegal stimulant was hidden underground in an “empty area” in the Ramtha district, Jordan's official news agency said on Sunday.
The report quoted police as saying that an investigation was under way to “identify those involved and apprehend them”. It did not give more details.
Security forces frequently conduct raids and other operations in northern Jordan to curb a multi-billion-dollar-a-year regional trade in Captagon and other drugs, which are manufactured mainly in Syria and Lebanon.
The border with Syria has become the main conduit for the trade since Syrian regime forces retook the area from rebels in 2018 after a deal between Russia, the US and Israel.
Jordan says pro-Iranian militia in southern Syria and the Syrian military are behind the rise in drug smuggling over the past four years. The 2018 agreement was supposed to keep Lebanon's Hezbollah and other Iran-backed groups away from the border.
Regional security officials say most of the drugs, particularly Captagon, pass through Jordan to Saudi Arabia, although a significant proportion are consumed in Jordan.
Earlier this month, Jordanian Foreign Minister Ayman Al Safadi told visiting Russian Foreign Minister Sergey Lavrov that Jordan hoped Moscow would help to maintain a “minimum stability” on its border with Syria.
He was referring to the flow of narcotics from areas controlled by President Bashar Al Assad's forces.
Russia has played a main role in a rapprochement between Amman and Damascus, which started last year. Moscow has been urging countries across the region to normalise ties with Damascus and pay for reconstruction, although the civil war is not over.
The conflict started in 2011 with mass demonstrations against five decades of Assad family rule.
Jordan announced it was lifting restrictions on commercial exchange with Syrian regime areas in the last quarter of 2021 and resumed high-level contacts. These culminated in a phone call between King Abdullah II and Mr Al Assad last October. Diplomats in Amman say the king raised the narcotics issue during the call.
But security officials say the Captagon trade has increased sharply this year, with Jordanian forces coming under increased attacks from smugglers along the Syrian border, prompting the military to escalate measures against infiltrators.