President Biden has greenlighted giving anti-personnel land mines to Ukraine in what is seen as a strategic move to push back Russian forces advancing through the eastern region.

An official for the Department of Defense tells the BBC that the mines would be delivered to the region soon, and that Ukrainian officials have said they would only deploy the explosive devices in their territory and away from major metropolitan centers. 

“They’ve asked for these, and so I think it’s a good idea,” Defense Secretary Lloyd Austin said to a group of reporters while in Laos on Wednesday, adding that the Ukrainian military is losing territory in the east.

“They have a need for things that can help that effort on the part of the Russians,” he said. 

The move by the Biden Administration is a reversal in previous policy to withhold distribution of the mines due to their tendency to outlast wars and cause harm to unsuspecting civilians. New precautions include rigging the mines to operate on an electric fuse and battery, which can run out of power over a few weeks, rendering them inactive.

On Tuesday, Ukrainian forces launched six American-made ballistic missiles at the Bryansk region of Russia, marking the first time they used the Army Tactical Missile System in Russian Territory after President Biden authorized Kyiv to use the missile outside its borders a day earlier. That move led Russian President Putin to issue a threat of the use of nuclear weapons.

“The Russian Federation reserves the right to use nuclear weapons in the event of aggression using conventional weapons against it and/or the Republic of Belarus,” Kremlin spokesman, Dmitry Perskov said on Tuesday.

The delivery of military supplies to Ukraine comes as The U.S. State Department announced that it would be closing its embassy in Kyiv after receiving intel of a potential airstrike on Wednesday.

“The U.S. Embassy in Kyiv has received specific information of a potential significant air attack on November 20, reads an alert issued by the State Department. “Out of an abundance of caution, the Embassy will be closed, and Embassy employees are being instructed to shelter in place.  The U.S. Embassy recommends U.S. citizens be prepared to immediately shelter in the event an air alert is announced.”

Similar warnings were issued at the beginning of the year and around Ukraine’s Independence Day last August.

Major drone attacks were also reported from both Russia and Ukraine overnight, but was not immediately known if there were any casualties.