U.S. Says Russia Is Firing Into Ukraine

WASHINGTON (AP) -- The Obama administration on Thursday accused Russia of firing artillery from its territory into Ukraine to hit Ukrainian military sites and asserted that Moscow is boosting its supply of weaponry to pro-Russian separatists.

"We have new evidence that the Russians intend to deliver heavier and more powerful multiple rocket launchers to separatist forces in Ukraine and have evidence that Russia is firing artillery from within Russian to attack Ukrainian military positions," State Department spokeswoman Marie Harf told reporters. She said the evidence derived from "human intelligence information" but declined to elaborate, saying it would compromise sources and methods of intelligence collection.

The allegations come amid an increasingly bitter war of words between Washington and Moscow over the crisis in Ukraine and conflicting claims over the downing of a Malaysian passenger jet over eastern Ukraine last week. The U.S. has repeatedly accused Russia of stoking the Ukraine rebellion and has said it believes separatists shot down the Malaysian plane, killing nearly 300 people, with a Russian provided surface-to-air missile.

Harf said Wednesday the ultimate responsibility for the downing of the plane rests with Russian President Vladimir Putin and the Russian government.