The embassy in Kyiv is urging the American citizens still in the country to leave immediately.
“If you hear a loud explosion or sirens being activated, seek shelter immediately,” writes the State Department in its warning.
“If you are in a residence or building, get to the lowest level with the least number of exterior walls, windows and openings, close all doors and sit near an interior wall with a distance from windows and openings.”
The warning comes after the US intelligence service declassified information that claims that Moscow intends to increase the bombing of civilian infrastructure in Ukraine, a US government source said.
Wednesday marks six months since the invasion began, a date that coincides with Ukraine’s Independence Day, which celebrates the nation’s liberation from Soviet rule.