EU foreign policy chief Josep Borrell will visit Ukraine's frontline this week in a show of support for Kyiv in the face of Moscow's military buildup on its border, Brussels said Monday.

Tensions have soared in recent months as the West has warned that Moscow could be planning a full-scale invasion of its neighbour after massing some 100,000 troops at the frontier. 

High-ranking officials from the United States and Russia are set to hold two days of talks in Geneva on the crisis starting Sunday after the Kremlin issued a raft of demands to Washington. 

Borrell -- who will meet Ukrainian officials in Kyiv during his visit from Tuesday to Thursday -- has insisted that "any discussion about European security must happen in coordination with and participation of EU".

Brussels fears it is being sidelined as the two nuclear powers discuss the balance of power in Europe in talks reminiscent of the Cold War era. 

Borrell will visit the "contact line" where Ukraine's armed forces face off against Russia-backed separatists. 

Russia seized the Crimea peninsula from Ukraine in 2014 and is accused of fomenting a bloody conflict in the east of the country that has killed over 13,000. 

Moscow insists that US-led military alliance NATO must rule out granting membership for ex-Soviet Ukraine and roll back its forces near Russia's border. 

The West has rejected what it calls a bid by Moscow to dictate the the future of independent allies and threatened Moscow with "severe costs" if it launches a fresh incursion of Ukraine.