WATCH: State Department says Russia’s use of Iran drones is ‘deeply concerning’

State Department Principal Deputy Spokesperson Vedant Patel said “Russia becoming more reliant on a country like Iran” should be deeply concerning to the world.

Watch the briefing in the player above.

“We will continue to take practical, aggressive steps to make these weapons sales harder, including sanctions, export control actions against any entities involved,” said Patel Tuesday.

This comes after Ukraine said Russia is getting thousands of drones from Iran.

The Iranian drones are precise, small, can effectively penetrate air defenses when fired in groups and are cheap at around $20,000 each.

Moscow has used them extensively in recent days in its war against Ukraine, especially against civilian targets in Ukrainian cities.

EXPLAINER: How Russia is using Iranian killer drones to spread terror in Ukraine

Ukraine’s military intelligence chief, Kyrylo Budanov, said that after Iran provided Russia with a first batch of 1,750 drones, Moscow has placed orders for more.

In the past week alone, more than 100 self-destructing Iranian-made drones have slammed into power plants, sewage treatment plants, residential buildings, bridges and other targets in urban areas, Ukraine’s Foreign Ministry said.

In a televised address on Monday night, Ukrainian President Volodymyr Zelenskyy said Russia is using the drones because it is losing ground in the war.

Patel also spoke about U.S. citizens Brittney Griner and Paul Whelan being held in Russian prison.

“The U.S. government continues to urge Russia to wrongfully, to release wrongfully detained U.S. citizens Brittney Griner and Paul Whelan,” said Patel.

“A consular officer had the opportunity today to speak with Brittney briefly on the phone. A consular officer also had the opportunity to briefly speak with Paul Whelan as well.”