Representatives from NATO countries and their allies are meeting to discuss increased military support for Ukraine.

Officials from about 50 countries gathered at NATO's headquarters in Brussels on Tuesday. Ukraine's defense minister Oleksii Reznikov was also in attendance.

At the beginning of the talks, US Defense Secretary Lloyd Austin reaffirmed that the United States and NATO allies will continue to support Ukraine in the long term.

He said, "That shared resolve will sustain Ukraine's momentum in the weeks ahead."

On Monday, NATO Secretary General Jens Stoltenberg suggested that Russian troops had already launched a large-scale offensive in the run-up to the one-year anniversary of their invasion.

Stoltenberg told reporters, "Key capabilities like ammunition, fuel and spare parts must reach Ukraine before Russia can seize the initiative on the battlefield. Speed will save lives."

The NATO chief said the meeting will likely cover the issue of whether countries should provide Ukraine with fighter jets. But he said such a discussion will take time and "what is needed now is urgent support for Ukraine."

NATO defense ministers will also hold separate talks for two days following the current meeting.

A number of countries have announced that they will give armored vehicles and tanks to the Ukrainian military.