MOSCOW, July 30 - Russia fought back on Wednesday over new U.S. and EU sanctions imposed over Ukraine even as G7 leaders warned of further steps, while Ukraine's government accused pro-Russian rebels of placing land mines near the site of a crashed Malaysian airliner to prevent a proper investigation, Reuters reported.

Russia announced a ban on most fruit and vegetable imports from Poland and said it could extend it to the entire European Union, a move Warsaw called Kremlin retaliation for new Western sanctions over Ukraine imposed on Russia on Tuesday.