BRUSSELS: NATO Secretary General Jens Stoltenberg said Tuesday he was "confident" the United States would keep up weapons deliveries to Ukraine, despite a political blockage in Washington.
The United States has provided over $40 billion in security aid to Ukraine since Russia's invasion and pledged to back Kyiv for as long as necessary.
But opposition from hardline Republicans has thrown into question the future of US assistance.
"I'm confident that the United States will continue to provide support because it is in the security interest of the United States to do so and it's also in line with what we have agreed," Stoltenberg said at a meeting of NATO foreign ministers in Brussels.
Concerns have ratcheted up over the future of Western backing for Ukraine as Kyiv's top general has admitted that the fierce fighting has ground to a "stalemate".
The European Union is currently also struggling to agree a plan for its own long-term support for arming Ukraine in the face of opposition from Hungary.
"I urge allies and allies are also committed to continue to deliver support," Stoltenberg said, pointing to 10 billion euros ($11 billion) pledged recently by Germany and the Netherlands.
"Even though the frontline has not moved so much, the Ukrainians have been able to inflict heavy losses on the Russian forces."
Latvian Foreign Minister Krisjanis Karins said Ukraine needs more "long-range missiles so that they can impede Russia's logistic capabilities".
"It's in our direct interest to continue supporting Ukraine to make sure that Russia does not win this war that Ukraine can win the war," he said.
Ukraine's top diplomat Dmytro Kuleba will join the meeting on Wednesday and NATO members are set to agree on a plan for reforms aimed at helping Ukraine towards eventual membership in the alliance.
Ukraine is pushing to join NATO, but the US-led alliance has so far refused to issue a formal invitation despite promising that Kyiv will be in its ranks one day.