As the war drags on, Ukraine has managed to hold off Russian gains for the past month thanks in large part to continued support from the United States and its European allies, and help on the ground from partisans.

Following months of grinding war in which Ukraine has lost territory, Kyiv has been able to stem Russian advances recently and force Russia to sustain heavy losses, with up to 500 Russian troops killed or injured every day, according to some estimates.

John Spencer, a retired Army officer and chair of urban warfare studies for the Madison Policy Forum research institute, said that while Ukraine has lost tactical ground in some regions, its troops have succeeded in weakening Russia’s military.

“They have also made Russians expend resources that they can’t replenish,” Mr. Spencer said. “You don’t want to say they’re winning the war because there’s so much fighting to be done, but from really every measure you think about, especially geopolitically and militarily, they’re achieving outweighed gains.”

Russia still maintains a huge advantage in the size of its weapons arsenal, and Ukraine has suffered heavily over the course of the war. As many as 200 soldiers were being killed each day at one point; the civilian death toll has topped 5,000, according to United Nations estimates; and several of the country’s cities have been flattened. But Moscow has had no major territorial gains since the capture of the eastern Luhansk Province in late June.

Ukraine was bolstered on Thursday when the defense ministers of 26 countries, including Britain and Denmark, pledged about $1.55 billion in military aid to Ukraine. Ben Wallace, Britain’s defense minister, said the aid would include additional multiple-launch rocket systems and long-range missiles.

“We are not getting tired,” Mr. Wallace said of his country’s continued support for Ukraine.

Morten Bodskov, Denmark’s defense minister, said his country would not just help with weapons, but that it would also assist in training service members.

The aid, which Mr. Zelensky has called for repeatedly since the war began, added to another package from the United States that was announced earlier this week. The Pentagon said on Monday that it would send more ammunition in a new shipment of up to $1 billion worth of weapons and supplies. With that, the United States will have sent more than $9 billion in aid to Ukraine since Russia invaded the country on Feb. 24.

Mr. Spencer said that maintaining such continued support from Western countries has taken “as much fighting as actually fighting Russian forces, as far as showing the world that they’re fighting a just war.”

Support for the country has not only come in the form of aid packages, but also through help on the ground in the form of partisans, resistance fighters who aid the Ukrainian military on Russian-occupied territory.

At least five fighter bombers and three multi-role jets were “almost certainly destroyed or seriously damaged” this week in blasts at an air base in Crimea, according to a British military intelligence report on Friday. Crimea — which Moscow annexed in 2014 — has largely avoided attacks since February and the base was far from any recognizable front line.

One senior Ukrainian official said the attacks were carried out with the help of partisans, but the government has not taken responsibility for the attack.

The Institute for the Study of War, a Washington-based think tank, has reported that “the Kremlin is scrambling to find any reinforcements” to replenish its decimated ranks of troops.

It said Saturday there were growing indications that Moscow would continue to expand the Kremlin’s direct control over Russia’s weapons manufacturers and other military-related industries as it tries to bolster a prolonged war effort.