KYIV, Ukraine (AP) — Russia pounded Ukraine's energy facilities Tuesday with its biggest barrage of missiles yet, striking targets across the country and causing widespread blackouts. A senior U.S. intelligence official said missiles crossed into NATO member Poland and killed two people.

A second person told The Associated Press that apparent Russian missiles struck a site in Poland about 15 miles from the Ukrainian border.

If confirmed, the strike would mark the first time in the war that Russian weapons have come down on a NATO country.

The Russian Defense Ministry denied being behind "any s...