NATO chief warns Russia away from attacking supply lines supporting Ukraine

NATO's secretary general has warned that a Russian attack on the supply lines of allied nations supporting Ukraine with arms and munitions would be a dangerous escalation of the war raging in eastern Europe.

Jens Stoltenberg made the remarks Tuesday in an interview with CBC News as he, Prime Minister Justin Trudeau and the leaders of Spain and Latvia visited NATO's base and training range at Adazi, outside Latvia's capital Riga.

"The allies are helping Ukraine uphold their right for self defence, which is enshrined in the UN charter," Stoltenberg said after a meeting with Trudeau, Spanish Prime Minister Pedro Sanchez and Latvian Prime Minister Arturs Krišjānis Kariņš at the Adazi base.

"Russia is the aggressor and Ukraine is defending itself. If there is any attack against any NATO country, NATO territory, that will trigger Article 5."

Article 5 is the self-defence clause in NATO's founding treaty which states that an attack on one member is an attack on all 30 member nations.

"I'm absolutely convinced President Putin knows this and we are removing any room for miscalculation, misunderstanding about our commitment to defend every inch of NATO territory," Stoltenberg said.

The United States and its allies, including Canada, have been engaged in a race against time to send weapons and ammunition to Ukraine, which has been under relentless assault from Russian forces for over two weeks.

Some in the U.S. intelligence community fear that Moscow might try to cut off the flow of arms going into Ukraine, either with airstrikes or with long-range artillery. The weapons coming from the West are unloaded in border countries, such as Poland, and then shipped by land.

Stoltenberg said there's a clear distinction between supply lines within Ukraine and those operating outside its borders.

"There is a war going on in Ukraine and, of course, supply lines inside Ukraine can be attacked," he said.

"An attack on NATO territory, on NATO forces, NATO capabilities, that would be an attack on NATO."

Stoltenberg said NATO's message to Russia is that "they have to end the war, that we will continue to support Ukraine and that we continue to impose unprecedented sanctions."

The stakes appeared to increase dramatically late Tuesday when Poland announced it is prepared to transfer all of its MiG-29 jets to the U.S. so that they can be handed over to the Ukrainians.

Poland's foreign ministry urged other NATO members with the same type of Russian-made warplanes to do the same.