NATO Secretary General Jens Stoltenberg, on an unannounced visit to Kyiv, said Thursday that Ukrainian forces were "gradually gaining ground" in their counteroffensive against Russian forces.

Speaking at a joint press conference with Ukrainian President Volodymyr Zelenskyy, Stoltenberg said "every meter that Ukrainian forces regain is a meter that Russia loses."

"And there is a stark contrast: Ukrainians are fighting for their families, their future, their freedom," he added. "Moscow is fighting for imperial delusions."

Zelenskyy stressed Ukraine's need for more air defense against Russian attacks, saying Moscow had used more than 40 Shahed drones in strikes on Ukraine the previous night alone.

"And so it is almost every night. In the conditions of such intense attacks against Ukrainians, against our cities, ports - which are important for global food security - we need a corresponding increase in pressure on Russia and a corresponding increase in our air shield," he said.

Stoltenberg said he was "constantly pushing" NATO allies to provide more support to Ukraine and speed up delivery, "not least" of air defense systems.

Stoltenberg announced that NATO now had over-arching framework contracts in place with arms companies worth 2.4 billion euros ($2.53 billion) for ammunition, including 1 billion euros in firm orders.

He said such contracts would allow NATO members to replenish their depleted stockpiles while also continuing to provide Ukraine with ammunition, a key factor in the war.

Stoltenberg also condemned Russian strikes near Ukraine's border with NATO member Romania. He said there was no evidence such strikes were a deliberate attack on Romania but branded them "reckless" and "destabilizing."