That zone would act as a defensive buffer before any enemy forces advanced into "a sort of hot zone" where traditional combat could happen, said General Thomas Lowin, NATO's deputy chief of staff for operations.

He was speaking to the German Sunday newspaper Welt am Sonntag.

The automated area would have sensors to detect enemy forces and activate defences such as drones, semi-autonomous combat vehicles, land-based robots, as well as automatic air defences and anti-missile systems, Lowin said.

He added, however, that any decision to use lethal weapons would "always be under human responsibility".

The sensors -- located "on the ground, in space, in cyberspace and in the air" -- would cover an area of several thousand kilometres (miles) and detect enemy movements or deployment of weapons, and inform "all NATO countries in real time", he said.

The AI-guided system would reinforce existing NATO weapons and deployed forces, the general said.

The German newspaper reported that there were test programmes in Poland and Romania trying out the proposed capabilities, and all of NATO should be working to make the system operational by the end of 2027.

NATO's European members are stepping up preparedness out of concern that Russia -- whose economy is on a war footing because of its conflict in Ukraine -- could seek to further expand, into EU territory.

Poland is about to sign a contract for "the biggest anti-drone system in Europe", its defence minister, Wladyslaw Kosiniak-Kamysz, told the Gazeta Wyborcza daily.

Kosiniak-Kamysz did not say how much the deal, involving "different types of weaponry", would cost, nor which consortium would ink the contract at the end of January.

He said it was being made to respond to "an urgent operational demand".