An Indian firm that shipped $1.4 million worth of an explosive compound with military uses to Russia in December said on Saturday it complies with Indian rules and the substance it had shipped was for civilian industrial purposes.

Reuters reported on July 24 that Ideal Detonators Private Limited shipped the compound, known as HMX or octogen, to two Russian explosives manufacturers despite US threats to impose sanctions on any entity supporting Russia's Ukraine war effort.

One of the Russian companies listed in Indian customs data as receiving the compound is the explosives manufacturer Promsintez. An official at Ukraine's SBU security service has said the Russian company has ties to the military and that Ukraine launched a drone attack in April against a Promsintez-owned factory.

Promsintez did not respond to a request for comment.

Ideal Detonators said in an emailed response to Reuters that the material it shipped was not military grade. "The shipment ... is for industrial activity and it's a civil explosive," the company said.

The US government has identified HMX as "critical for Russia's war effort" and has warned financial institutions against facilitating any sales of the substance to Moscow.

The US Treasury Department has the authority to sanction those who sell HMX and similar substances to Russia, sanctions lawyers have said.

HMX is widely used in missile and torpedo warheads, rocket motors, exploding projectiles and plastic-bonded explosives for advanced military systems, according to the Pentagon's Defense Technical Information Center and related defense research programs. The compound also has some limited civilian applications in mining and other industrial activities.