Ukraine's military claimed Tuesday for the first time that it encountered an Iranian-supplied suicide drone used by Russia on the battlefield, showing the deepening ties between Moscow and Tehran as the Islamic Republic's tattered nuclear deal with world powers hangs in the balance.

U.S. intelligence publicly warned back in July that Tehran planned to send hundreds of the bomb-carrying drones to Russia to aid its war on Ukraine. While Iran initially denied it, the head of its paramilitary Revolutionary Guard has boasted in recent days about arming the world's top powers.

The Ukrainian military's Strategic Communications Directorate published images of the wreckage of the drone. It resembled a triangle, or delta-shaped, drone flown by Iran known as the Shahed, or “Witness” in Farsi.

The military official and the website both said Ukrainian troops encountered the drone near Kupiansk amid Kyiv's offensive that has punched through Russian lines around Kharkiv on the eastern front.

The image suggested the Shahed drone had been shot down by Ukrainian forces and hadn't detonated on impact as designed, though little other information was immediately released by Kyiv. An inscription on the drone identified it as an "M214 Gran-2," which didn't immediately correspond to known Russian weaponry.

Iran's mission to the United Nations did not immediately respond to a request for comment.

Iran has multiple version of the Shahed, which have overflown a U.S. aircraft carrier in the Persian Gulf, been used by Iranian-backed rebels in Yemen, attacked oil depots in Saudi Arabia and allegedly killed two sailors aboard an oil tanker off Oman in 2021. The triangle-shaped Shahed is believed to have a range of around 2,000 kilometers (1,240 miles), though Iran has offered few details.

Experts refer to such bomb-carrying drones as “loitering munitions.” The drone flies to a destination, likely programmed before its flight, and either explodes in the air over the target or on impact against it.

Iran has drawn closer to Russia as it faces crushing sanctions over the collapse of the nuclear deal in 2018 after then-President Donald Trump unilaterally withdrew from the accord. Negotiations over the deal, which saw Iran limit its enrichment of uranium in exchange for sanctions being lifted, again appear deadlocked.

Ukraine and Iran also have tense relations, stemming from Iran's Revolutionary Guard shooting down a Ukrainian passenger jet in 2020, killing all 176 people on board.