New Delhi, Feb 27 (IANS): UK Armed Forces Minister James Heappey said Putin's "days are numbered" if he fails in Ukraine, with his campaign falling "well behind" its planned timeline and was facing several severe headwinds, Daily Mail Reported.

Heappey, a former major in the Rifles, said Putin's forces had been unable to capture key cities in the first few days of fighting as intended and had left pockets of 'well-armed' Ukrainians to the rear of their front line, the report said.

A picture is emerging of a haphazard and disorganised invasion effort, with armoured columns running out of fuel or getting lost, and some having to advance without air cover, Daily Mail reported.

Heappey wrote in the Telegraph: "After three days of intense fighting, spurred by dogged Ukrainian resistance, Russia is well behind its planned timeline."

"Progress to Kyiv has been much slower than they'd expected, they were unable to take key cities early and now must try to bypass them."

"This leaves pockets of well-armed and well-trained Ukrainians to the rear of the Russian front line, exposing a vulnerable logistics tail - an omen for what awaits Putin."

At the same time, Ukrainians are volunteering in their droves, with 'long queues' at recruitment centres, the minister wrote, Daily Mail reported.