RAMSTEIN AIR BASE, Germany (AP) — Defense Secretary Lloyd Austin urged allied defense leaders Tuesday to “dig deep" and provide more air defense systems for Ukraine, to help the country block increasing barrages of Russian missiles.

But while the allies said they will discuss how they can best help Ukraine's counteroffensive, they appeared no closer to commitments on the longer-range missiles that Kyiv's leaders insist they need.

“Air defense is saving lives,” Austin said as he opened the meeting of the Ukraine Defense Contact Group at Ramstein air base in Germany. “So I urge this group to continue to dig deep on ground-based air defense for Ukraine. We must continue to push hard to provide Ukraine with air-defense systems and interceptors.”

The group is made up of the defense and military leaders from more than 50 nations and is the main forum for raising contributions of weapons, other equipment and training for Kyiv’s war effort. It meets about once a month, in person and virtually, and this is the 15th gathering.

President Volodymyr Zelenskyy and other Ukrainian leaders have repeatedly pushed for the longer-distance weapons. Proponents have argued that Ukrainian forces need to be able to strike Russian troops and facilities while still staying out of range.

But the U.S. has continued to balk, expressing longstanding worries that Kyiv could use the weapons to hit deep into Russian territory and enrage Moscow. The Army Tactical Missile System, known as ATACMS, could give Ukraine the ability to strike Russian targets from as far away as about 180 miles (300 kilometers), but the U.S. also has other variants of the missile that have a shorter range.

Speaking before the meeting began, Bill Blair, the Canadian defense minister, told reporters that the allies are listening to Ukrainian leaders' descriptions of their military needs and are discussing “new and important ways” to help bolster the ongoing counteroffensive.

Austin said the 31 M1 Abrams tanks promised months ago will soon begin arriving in Ukraine, as has been expected. A defense official said they have arrived in Europe and will begin crossing the border into Ukraine within the coming days. The official spoke on condition of anonymity because the precise location of the tanks is sensitive.

Ukrainian troops began training on similar tanks in June, while the ones arriving soon were being refurbished in the U.S.

Defense leaders are working to continue what they say is unbowed support of Ukraine, despite growing worries that public and international government backing for the war, which is well into its second year, may be starting to wane.

Zelenskyy will be in Washington, D.C., later this week to meet with President Joe Biden and congressional leaders in a move to shore up support for continued American funding and weapons. The visit comes as there is a growing partisan divide in Congress over continued Ukraine funding.

Republican House Speaker Kevin McCarthy has told reporters that he wants more aid for Ukraine to be debated on its own merits as a standalone bill, rather than attaching it to other priorities like government funding. But Senate leaders want to combine the aid with other priorities, such as a short-term spending bill that will likely be needed to avoid a shutdown at the end of September.

Nations have been pouring millions of rounds of artillery and other weapons into Ukraine, but worry that their stockpiles are shrinking and the defense industry is struggling to boost production lines. At the same time, Ukrainian forces have been making slow progress breaking through Russian battle lines in a counteroffensive that has not moved as quickly or as well as initially hoped.

“Ukraine’s recent gains also hinge on the crucial capabilities provided by the members of this Contact Group," Austin said at the Ramstein opening. "And our shared commitment will be vital during the current battles — and for the long road ahead.”

Military leaders, including Army Gen. Mark Milley, chairman of the Joint Chiefs of Staff, have pushed back on the criticism that the offensive has moved too slowly, arguing that Ukraine troops are making steady progress in a difficult fight. This, Milley has said, is real war and Ukrainian forces are carefully pushing their way through large and deadly Russian minefields.

At the close of a meeting of NATO military chiefs on Saturday, Adm. Rob Bauer of the Netherlands, who chairs the alliance's Military Committee, acknowledged that nations have to weigh the risks of providing Ukraine more weapons without risking their own security needs.

The Ramstein meeting also marks Milley's final session as U.S. joint chiefs chairman. He will retire at the end of the month, at the close of four years on the job.