Over 40 per cent of the Russian forces on the borders of Ukraine are now in position for attack, and Moscow has initiated a campaign of destabilization, a U.S. defence official said Friday.

While the United States is assuming that Russia has deployed more than 150,000 troops on the Ukrainian borders and has observed major movements since Wednesday, insisting on anonymity.

The official further added, “Around 40-45 per cent are in an attack position. They have uncoiled in the tactical assembly in the last 48 hours.”

Tactical assembly points are the areas in the region that are almost next to the border where military units are set up in advance of an attack.

The official further added that Moscow has deployed over 125 battalion tactical groups close to the Ukraine border, compared to 60 in regular times and set up from 80 at the starting of February.

At the same time, the increase in clashes between pro-Rusian separatists and Ukraine government forces in the southeastern Donbas region of Ukraine, and inflammatory claims by officials in Russia and Donbas, shows that “the destabilization campaign has begun,” the official said.

Washington has been alerting for a long that Russia could provoke an incident in the region to serve as a pretext for invading Ukraine.

Meanwhile, U.S. Secretary of Defense Lloyd Austin said that, “Russian President Vladimir Putin has a number of options available to him in order to launch an attack at any time.”

Austin added that “I don’t believe it’s a bluff. I think he’s assembled, the kind of things that you would need to conduct a successful invasion.”

At the same time, Moscow denies that it has plans to attack its western neighbour but is demanding assurance that Ukraine will never join NATO and that the Western alliance removes forces from Eastern Europe, demands the West has refused.