The US embassy in Kyiv has temporarily closed after receiving "specific information of a potential significant air attack on 20 November".
"Out of an abundance of caution, the embassy will be closed, and embassy employees are being instructed to shelter in place," it said in a statement., external
The embassy also recommended that US citizens should prepare to shelter in the event an air alert is announced.
https://www.bbc.com/news/live/c20726y20kvt?post=asset%3A800e1f90-8a42-4df7-b56a-b79f41bef94a#post