The Pentagon has rejected an assertion by Russia that that US troops were training Ukrainian forces in the eastern Ukraine.

“This is a ridiculous attempt to shift the focus away from what is actually happening in eastern Ukraine,” Pentagon spokeswoman Eileen Lainez told reporters on Thursday.

Lainez made the remarks after a Russian defense ministry spokesman said earlier the day that Ukrainian forces are being trained by US troops not only in western Ukraine “as Ukrainian TV channels show, but directly in the combat zone in the area of Mariupol, Severodonetsk, Artyomovsk and Volnovakha”.

However, Lainez rejected the idea of US involvement in any mission in the combat zone in the east but confirmed that the Pentagon is conducting a program to train Ukrainian guardsmen in the western part of the country.

Also on Wednesday, the US State Department accused Russia of building up its forces along its border with Ukraine and increasing its air defense systems to the highest levels.

“The Russian military has deployed additional air defense systems into eastern Ukraine and moved several of these nearer the front lines,” said State Department spokeswoman Marie Harf.

Harf also said this is the highest amount of Russian air defense equipment in eastern Ukraine since August.

In a Wednesday phone call, US Secretary of State John Kerry told his Russian counterpart Sergei Lavrov that Russia must withdraw its forces from eastern Ukraine.

Washington also accused Moscow of training pro-Russia forces in eastern Ukraine of violating the terms of the Minsk ceasefire agreement signed by Kiev and the militias in February.

The allegation was made after 300 American paratroopers on Monday started training Ukrainian National Guard forces to fight pro-Russia militias in eastern Ukraine.

The United States has provided $75 million worth of military aid to Ukraine, but has so far stopped short of sending lethal weapons.

The Kremlin has warned that the US involvement could further “destabilize” Ukraine, where the conflict has killed more than 6,000 people in the past year.

The US and its allies have repeatedly accused Moscow of sending troops into eastern Ukraine in support of the pro-Russia forces. Moscow, however, denies any involvement.

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