The Pentagon said $250 million will be released to assist with Ukraine's defensive capabilities, air and sea surveillance, communication and cyberdefense, the latter "to counter Russian cyber offensive operations and misinformation. "

The support will complement NATO security assistance to Kiev, and comes after the US certified the Ukraine government had implemented required reforms in the military, the Pentagon said.

Over the past year, Ukraine has taken "considerable steps" to strengthen civilian control of the military; reform management and command structures, and reduce corruption, it said.

The West has expanded its support of the Ukraine military since Russian troops invaded Ukraine's strategic Crimea region and claimed the territory for itself in 2014.

Moscow is also accused of supporting rebels who control parts of the country's east.

Last year Trump froze $400 million in military aid to the country while he sought help from the government to smear former US vice president Joe Biden, his Democratic challenger in the November presidential election.

Trump was impeached in the House of Representatives for abuse of power and placed on trial in the Senate, where overwhelming support from his Republican Party led to his acquittal.

The $400 million has since been reduced to $250 million.