Up to half of Russian troops near Ukraine border in 'attack positions' - US official

Forty to fifty percent of Russian troops near its border with Ukraine are in "attack positions," a US defense official said on Friday.

Western countries fear a conflict if Russia invades Ukraine on a scale unseen in Europe at least since the Yugoslav and Chechen wars of the 1990s, which killed hundreds of thousands of people and forced millions to flee.

The official, speaking on the condition of anonymity, said there were roughly 150,000 Russian troops on the border, which included about 125 battalion tactical groups.

The percentage of forces in attack positions is higher than previously known and suggests those Russian units could attack Ukraine with little to no warning.

The official did not provide evidence for the assessment and did not specify if the attack positions were on the border with Ukraine or in separatist-held parts of eastern Ukraine.