An air raid alert was declared in all of Ukraine on Friday as officials warned of potential Russian missile strikes, urging residents to take shelter.

"There is a big threat of the missile attack. I want to stress again - do not ignore the air alert sirens," said Serhiy Popko, head of Kyiv city military administration. (Reporting by Olena Harmash; Editing by Muralikumar Anantharaman)