LONDON, November 12. /TASS/. Former NATO Secretary General Anders Fogh Rasmussen said NATO should invite Ukraine to join the alliance without the territories it no longer controls, according to an interview published by the Guardian.

"The time has come to take the next step and extend an invitation for Ukraine to join NATO," he told the Guardian. "We need a new European security architecture in which Ukraine is in the heart of NATO."

"The absolute credibility of Article 5 guarantees would deter Russia from mounting attacks inside the Ukrainian territory inside NATO and so free up Ukrainian forces to go to the frontline," said Rasmussen, who headed the bloc from 2009-2014.

He said the alliance would have to send a "clear message to Russia that any violation of NATO territory would be met by a response." He added that in some ways the proposal is similar to imposing a no-fly zone over Ukrainian territory.

Rasmussen insisted that the move would not freeze the conflict or force Ukraine to cede territory to Russia.

The Guardian said Rasmussen worked alongside Andrey Yermak, the chief of staff of the Ukrainian presidency, ahead of the last NATO summit in Vilnius this year that ended with no invitation for Ukraine to join.