Iran has been accused of concealing military equipment as “humanitarian aid” to smuggle weaponry into Syria for use by proxy groups in attacks on U.S. troops, according to leaked documents obtained by military intelligence. The Pentagon has confirmed the authenticity of the documents, which were discovered on Discord in April and reported by The Washington Post.

The alleged scheme took place following a catastrophic earthquake in February that killed tens of thousands of people in the region. With an abundance of aid flowing in and out of Syria, Iran reportedly shipped weapons disguised as humanitarian supplies.

Iran’s alleged smuggling of weapons into Syria included unspecified small arms, ammunition and drones, according to the leaked U.S. intelligence assessment. The document also said those deliveries were made using vehicle convoys from Iraq coordinated through friendly militant groups in the region. Iraqi Prime Minister Mohammed Shia al-Sudani’s office would not comment on record but a senior official dismissed the smuggling allegations as “fake.”

“In reality the borders are wide open. In fact, we are still suffering from illegals sneaking through the Syrian border,” the Iraqi official said. “Which means if these documents are right, it’s possible any time. Why wait for an aid convoy as a justification?”

The leaked documents have raised concerns about the ability of the United States to intercept Iranian-sourced military equipment that is regularly used to target American troops. Reuters reported in April that Tehran had allegedly used cargo planes to smuggle air defense systems into Syria, once again disguised as a shipment of “earthquake relief.” Iranian officials have denied these claims.

“Under the guise of shipments of earthquake aid to Syria, Israel has seen significant movements of military equipment from Iran, mainly transported in parts,” an Israeli defense official told Reuters.

The alleged heavy-weapons transfers could further endanger the 900 U.S. troops stationed in Syria. In March, a U.S. contractor working at a military base there was killed by an Iranian-made drone, according to the Pentagon. The air defense system at the base failed to engage the drone, and it remains unclear why.