That’s much longer than many officials had expected even early this year, but slow progress in Ukraine’s counteroffensive in recent months has tempered expectations.

G-7 officials discussed the darker outlook at a dinner on the sidelines of the United Nations General Assembly Monday night and agreed that the conflict is likely to last for the medium or long term, a senior US State Department official told reporters Tuesday. The officials requested anonymity to discuss matters that aren’t public.

The US and European Union have injected tens of billions of dollars in military and humanitarian aid to Ukraine to help it repel Russia’s invasion, which is now in its second year, while avoiding direct action that would widen the scope of the conflict.

Allies provided weapons and training for Ukraine’s counteroffensive, but Kyiv’s forces have struggled to break through Russia’s elaborate defensive lines. Time is running short ahead of cold, rainy weather in the autumn that would complicate military operations.

“The Ukrainians have penetrated several layers of defense. It is not 100% penetrated yet, but they’ve penetrated several of the layers,” Chairman of the US Joint Chiefs of Staff General Mark Milley said. He spoke alongside Secretary of Defense Lloyd Austin after the conclusion of a meeting of the Ukraine Defense Contact Group in Germany.

Long-term assistance to Ukraine will include energy and infrastructure aid and is expected to bolster the country’s economy to deter Russia in the future, the US official said.

The European Union over the summer announced an additional €50 billion ($53 billion) support package for Ukraine to be delivered through 2027, which doubles total EU commitments. Germany, Ukraine’s second-biggest supporter in the fight after the US, has pledged to provide €5 billion annually through that period.

In the US, President Joe Biden is seeking $24 billion in support for Ukraine for the fiscal year starting Oct. 1, but opposition to continued spending is facing growing opposition in Congress.

Ukrainian President Volodymyr Zelenskiy is among leaders in New York this week, where he’ll seek to rally nations to the war effort. That includes a meeting scheduled for Wednesday with Brazil’s President Luiz Inacio Lula da Silva, a prominent leader of the so-called Global South who has so far refused to pick sides.

UN Secretary General Antonio Guterres on Tuesday called Russia’s invasion a violation of the UN charter and international law. “Ignoring global treaties and conventions makes us all less safe,” he said. “And the poisoning of global diplomacy obstructs progress across the board.”