NATO allies have agreed that Ukraine will become a member of the Alliance in the long term perspective, NATO Secretary General Jens Stoltenberg has said.

"NATO allies have agreed that Ukraine will become a member of our alliance, but at the same time that that is a long term perspective, what is the issue now is to ensure that Ukraine prevail as a sovereign, independent nation, and therefore we need to support Ukraine," he said at a press conference with Finnish Prime Minister Sanna Marin in Helsinki, the NATO press service reported.

The Secretary General also said that "we are not party to the conflict but we need to remember what this is."

"This is a war of aggression launched by President Putin against Ukraine. They have the right to defend themselves. That is right, which is enshrined in the UN Charter, and we have the right to help support Ukraine in upholding the right of self-defence," he said.

Stoltenberg said that at the same time, NATO has another task - to prevent an escalation, "prevent this from becoming a full fledged war between Russia and NATO."

"Therefore, we have also increased our military presence in the eastern part of the Alliance, also in the Baltic region to send a clear message that an attack on a NATO Ally will trigger the response from the whole Alliance," the Secretary General said.

He also added that "no one can tell exactly when this war ends, but when it ends, we need to ensure that history doesn't repeat itself that President Putin cannot continue to attack neighbours."

"And therefore we need to strengthen the military capabilities of Ukraine, but also look for frameworks that can ensure that President Putin, Russia doesn't invade Ukraine yet another time," he said.