Tells US citizens to be prepared to immediately shelter in event air alert is announced

Nov. 20 (UPI) -- The U.S. Embassy in Kyiv closed on Wednesday after receiving "specific information of a potential significant air attack," it said, as the Kremlin warned it would retaliate after the Biden administration reportedly permitted Ukraine to strike deeper within Russia.

The U.S. Embassy in Kyiv, Ukraine, has released a warning stating that they have "specific information of a potential significant air attack" taking place on Wednesday, Nov. 20.

The U.S. Embassy in Kyiv said it has received warning of a potentially significant Russian air attack on Wednesday and would be closed as a precaution. In a statement, the embassy also instructed employees to shelter in place and also recommended that U.S. citizens in Kyiv be prepared to immediately shelter in the event of an air alert. The warning was unusual for its specificity as Russian air attacks have become a common, near-daily occurrence in Ukraine.

'The U.S. Embassy in Kyiv has received specific information of a potential significant air attack on November 20,' it said in a message on its website.