The United States believes Russia used a short range ballistic missile to strike a railway station in east Ukraine on Friday, a senior U.S. defense official said.
Ukraine said at least 50 people were killed and many more wounded in a strike on a station in the city of Kramatorsk that was packed with civilians hoping to flee the threat of a major Russian offensive.
Motivation for Attack not Clear
The U.S. defense official, speaking on condition of anonymity, said the Pentagon believes Russian forces used an SS-21 Scarab missile in the strike but that the motivation for the attack was not clear.
The SS-21 is the name used by the NATO military alliance for a type of missile known as the Tochka in former Soviet states.
The United States was still analyzing the strike and it was unclear whether cluster munitions were used, the U.S. official said.
"We are not buying the denial by the Russians that they weren't responsible," the official said.
The Russian defense ministry was quoted by RIA news agency as saying the missiles said to have struck the station were used only by Ukraine's military and that Russia's armed forces had no targets assigned in Kramatorsk on Friday.
Videos posted on social media in recent weeks, which Reuters could not independently verify, appear to show Russian forces in or near Ukraine transporting Tochka missile launchers.
Assembled more than 150,000 Troops
The U.S. defense official said Russia's combat power in Ukraine continued to decline and was somewhere between 80% and 85% of its pre-invasion levels.
The United States has estimated Russia assembled more than 150,000 troops around Ukraine before its invasion on Feb. 24.
The official said the United States now had indications Moscow has started mobilizing some reservists and could be looking to recruit more than 60,000 personnel.
Russian forces who had been in the Kyiv region were heading to Belarus and parts of western Russia, such as Belgorod, to be refitted and resupplied, the official said.
But the Pentagon believes Moscow has yet to solve the logistics problems that have hampered their invasion since its start, the official said.
"We've seen indications of some units that are literally, for all intents and purposes, eradicated."