WASHINGTON (AP) — For the first time since Defense Secretary Lloyd Austin established the international group to support Ukraine in April 2022, the United States is hosting the monthly gathering of about 50 countries out of money, unable to send the ammunition and missiles that Ukraine needs to fend off Russia's invasion.

While waiting for Congress to pass a budget and potentially approve more money for Ukraine's fight, the U.S. will be looking to allies to keep bridging the gap.

"I urge this group to dig deep to provide Ukraine with more lifesaving ground-based air defense systems and interceptors," Austin said in opening remarks broadcast from his home, where he is still recuperating after prostate cancer surgery. The opening statement by video was the first public appearance from Austin, 70, who appeared slightly gaunt. Austin was hospitalized for two weeks after complications from the surgery.

On Tuesday in Brussels, NATO Secretary General Jens Stoltenberg announced a new $1.2 billion joint contract to buy more than 222,000 rounds of 155 mm ammunition. The rounds are some of the most heavily used munitions in this conflict, and the contract will be used to backfill allies that have pushed their own reserves to Kyiv.

"Even though we aren't able to provide our security assistance right now, our partners are continuing to do that," deputy Pentagon press secretary Sabrina Singh told reporters Monday.

While the conflict between Israel and Hamas has dominated headlines since October, Russia's bloody onslaught of Ukraine has continued.

Russia on Tuesday launched a barrage of more than 40 ballistic, cruise, anti-aircraft and guided missiles into Ukraine's two biggest cities, damaging apartment buildings and killing at least five people. The assault came a day after Moscow shunned any deal backed by Kyiv and its Western allies to end the almost two-year war.

Ukraine's air defenses were able to intercept at least 21 of the missiles, however the attacks injured at least 20 people in four districts of Kyiv, the capital.

Additional air defense systems and munitions for them remain a top need of Ukraine, Singh said.

The Pentagon announced its last security assistance for Ukraine on Dec. 27, a $250 million package that included 155 mm rounds, Stinger anti-aircraft missiles and other high-demand items drawn from existing U.S. stockpiles.

The U.S. has not been able to provide additional munitions since then because the money for replenishing those stockpiles has run out and Congress has yet to approve more funds.

More than $110 billion in aid for both Ukraine and Israel is stalled over disagreements between Congress and the White House over other policy priorities, including additional security for the U.S.-Mexico border.

The U.S. has provided Ukraine more than $44.2 billion in security assistance since Russia invaded in February 2022. About $23.6 billion of that was pulled from existing military stockpiles and almost $19 billion was sent in the form of longer-term military contracts, for items that will take months to procure. So even though funds have run out, some previously purchased weapons will continue to flow in. An additional $1.7 billion has been provided by the U.S. State Department in the form of foreign military financing.

The U.S. and approximately 30 international partners are also continuing to train Ukrainian forces, and to date have trained a total of 118,000 Ukrainians at locations around the world, said Col. Marty O'Donnell, spokesman for U.S. Army Europe and Africa.

The United States has trained approximately 18,000 of those fighters, including approximately 16,300 soldiers in Germany. About 1,500 additional fighters are currently going through training.