A drone factory that Iran is helping Russia build could be operational next year, the U.S. says.

WASHINGTON — The military partnership between Moscow and Tehran is deepening, White House officials said on Friday as they released newly declassified information about a drone factory that Iran is helping Russia build.

Russia has repeatedly used Iranian-made drones to attack Ukraine in recent months, including strikes on civilian targets, buildings and electrical infrastructure as part of a push to break Ukrainian morale. And as Moscow’s own weapons stocks have diminished, Iran has become a key supplier of military aid to Russia.

The new factory, which is planned for a warehouse in the Yelabuga region several hundred miles east of Moscow, would allow Russia’s military to have its own domestically produced source of attack drones. Iran is providing materials for the plant, said John Kirby, the National Security Council spokesman, who added that the facility could be operational next year.

Plans for the plant have been known for some time. The Wall Street Journal reported plans for a potential drone factory in Yelabuga in February, and the White House released a satellite image of the factory’s intended site that was dated in early April.

An examination of satellite imagery by The New York Times shows a series of new buildings constructed in the industrial area since 2021. Construction on the buildings highlighted by the White House in the declassified intelligence started at the end of January 2021, and a small structure was recently added, the Times review showed.

By releasing the declassified information, American officials are trying to raise the pressure on Iran and make it more difficult to complete the work. On Friday, Mr. Kirby also said the United States would release a new advisory intended to help businesses around the world ensure that “they are not inadvertently contributing” to Iran’s drone program.

A key part of America’s strategy for helping Ukraine is to prevent Russia from gaining access to new military equipment or rebuilding its depleted stocks. And hindering trade between Russia and Iran is one of the most important elements of that effort.

Currently, according to the White House, Russian ships transport drones from Amirabad, Iran, across the Caspian Sea to Makhachkala, Russia. From there, they are transported to two bases: one northeast of Ukraine and one east of Ukraine. They are then used to attack Ukrainian targets.

Mr. Kirby said the arms trade between Iran and Russia was flowing both ways.

“Russia has been offering Iran unprecedented defense cooperation, including on missiles, electronics and air defense,” he said, adding that Iran had finalized a deal to buy Su-35 fighter jets from Russia and was seeking attack helicopters, radars and combat trainer aircraft.

Washington believes that the drone purchases are violations of United Nations Security Council resolutions and has imposed sanctions on Iranian companies involved in designing, building and transporting the drones.

Mr. Kirby described the cooperation between Iran and Russia as “a full-scale defense partnership that is harmful to Ukraine, to Iran’s neighbors and to the international community.”