BRUSSELS, June 14 (Xinhua) -- NATO defence ministers on Tuesday agreed to deploy four multinational battalions to the Baltic states and Poland, NATO Secretary General Jens Stoltenberg announced at a press conference following the ministerial meeting.

"I welcomed the commitments made by many Allies today to contribute," said Stoltenberg, without confirming the overall size, the scope and the composition of the force to be sent.

He stressed that this sends a clear message that if any Ally is attacked, the whole Alliance will respond as one.

The battalions will under NATO command and be deployed on a rotational basis.

Increasing its presence in the Baltic region is one element of a more comprehensive adaptation of NATO deterrence and defence in light of the Ukraine crisis.

Stoltenberg said NATO has now fully implemented the Readiness Action Plan aiming to strengthen the bloc's collective defense, adopted at the Wales Summit two years ago. Today, he added, Allies are taking the next steps.

He stressed that NATO's defence and deterrence posture is full-spectrum, including conventional capabilities and nuclear dimension.

NATO ministers also agreed to recognise cyberspace as an operational domain at the Warsaw Summit.

Noting that NATO's efforts to boost its deterrence and defence depend on the right capabilities and resources, Stoltenberg underlined that, after many years of constant cuts in defence spending, the Alliance is now back on the right track.

"In 2015 we saw a small increase in defence spending across European Allies and Canada. And our estimates indicate a further increase in defence spending in 2016," he said.