The Iranian regime has developed chemical weapons based on opioids, including fentanyl, and could supply them to its regional terrorist proxies including Hamas and Hezbollah, a U.S. expert warns.

Pharmaceutical-based agents, or PBAs, are weaponised drugs with the ability to incapacitate or kill their victims, Hamas expert Matthew Levitt explained in October's CTC Sentinel, a journal published by the U.S. Military Academy at West Point's Combating Terrorism Center.

Levitt serves as the director of the Reinhard Programme on Counterterrorism and Intelligence at the Washington Institute for Near East Policy and has testified for the U.S. government in numerous terrorism trials since the early 2000s.

The article, which was picked up by US media on Sunday, warned that "groups such as Hezbollah already have the delivery systems necessary to deploy such chemicals, including grenade launchers and mortars."

PBAs affect the central nervous system, and once inhaled, they "cause victims to lose full consciousness and enable the forces deploying them to advance quickly and quietly and/or take captive the unconscious victims," Levitt wrote in his article titled "Tehran's Tactical Knockout."

An Israel Defence Forces official told the author that Hezbollah already possesses tear-gas dispersal systems such as grenades and mortars and could use these as delivery systems for weapons laced with PBAs.

Israel's military was said to have already been acting on the assumption that Hezbollah has such systems and has deployed them to the field for use in operations to kidnap IDF soldiers deployed along the border or as part of a plan to infiltrate the Jewish state in an "October 7-style attack."

Israeli President Isaac Herzog revealed last year that IDF troops found instructions for producing cyanide poison gas on the corpse of one of the Hamas terrorists who participated in the Oct. 7, 2023, massacre.

Speaking with Britain's Sky News, the Israeli head of state said that the IDF found a USB flash drive with instructions for preparing a device to disperse the gas, once used for mass murder in Nazi gas chambers.

Meanwhile, the Israeli Foreign Ministry's weapons of mass destruction non-proliferation department informed the Jewish state's embassies of "Hamas's intention to use chemical weapons" in a classified cable, reports said.

In July, an Iranian source told Kuwait's Al-Jarida newspaper that Iran's Islamic Revolutionary Guard Corps delivered a shipment of "qualitative weapons" to Tehran's Lebanon-based Hezbollah terrorist army.

The arms shipment reportedly included bombs and missiles carrying electromagnetic pulse (EMP) warheads. The weapons could be used against U.S. and British troops coming to Israel's aid, the source said.