KYIV, UKRAINE -- A dayslong attempt by Russian forces to storm a strategically important city in eastern Ukraine appears to be running out of steam, Kyiv officials said Monday, .

Ukrainian forces repelled 15 Russian attacks from four directions on Avdiivka over the previous 24 hours, the Ukrainian General Staff said.

That compared with up to 60 attacks a day in the middle of last week, according to Vitalii Barabash, head of the city administration. The slackening suggests the Russian effort to capture Avdiivka has "deflated," Barabash said.

A Washington-based think tank broadly concurred with that assessment. "Russian forces continued offensive operations aimed at encircling Avdiivka ... but have yet to make further gains amid a likely decreasing tempo of Russian operations in the area," the Institute for the Study of War said in an analysis published late Sunday.

Russia's ambassador to the United Nations, Vassily Nebenzia, told a UN Security Council meeting last Friday that the ramped-up attacks in the east amounted to a new stage in Moscow's campaign in Ukraine.

With the looming onset of wintry conditions that will limit military operations, both sides have been seeking battlefield breakthroughs that could invigorate their efforts and raise morale.

Ukraine launched its own counteroffensive about four months ago. It has made some headway but the limited success has underlined the daunting challenge of taking on the Kremlin's more numerous forces.

Kyiv's western allies insist that their military and financial support for Ukraine will continue, even as the Israeli-Hamas war rages and competes for resources.

U.S. national security adviser Jake Sullivan said Sunday the Biden administration will ask Congress for a combined aid package for Ukraine and Israel worth more than US$2 billion.

Ukrainian officials have said their troops are holding out against fierce Russian efforts to wrest control of Avdiivka, a heavily fortified city.

Avdiivka lies in the northern suburbs of the city of Donetsk, in a region of the same name that Russian forces partially occupy. Avdiivka's location grants Ukrainian forces artillery advantages over the city and could serve as a springboard for them to liberate Donetsk.

It is not possible to verify battlefield claims by either side. Misinformation and disinformation have played a central role in the war.

Russian Defence Minister Sergei Shoigu, speaking during a meeting with Russian President Vladimir Putin, claimed Ukrainian forces have failed to make any significant gains during their counteroffensive. Kyiv's troops are trying to make headway without air cover and have encountered multi-layered Russian defences.

Putin, in an interview with the China Media Group released Monday, claimed that Ukraine's counteroffensive has achieved "no results so far, only massive losses."

Moscow can expect more diplomatic pressure from the 57-nation Organization for Security and Cooperation in Europe in coming months, according to the chief diplomat of North Macedonia, which currently holds that body's rotating presidency.

The country's foreign minister, Bujar Osmani, urged Russia to cease its attacks on Ukraine and withdraw its forces. He spoke at a press conference in Kyiv on Monday.

The OSCE was created during the Cold War to help to defuse tensions between East and West.

Meanwhile, Russian children's rights ombudswoman Maria Lvova-Belova claimed Monday that her office has helped 35 Ukrainian children reunite with their relatives in Ukraine and other countries.

Lvova-Belova, who was indicted along with Putin by the International Criminal Court for war crimes connected to the deportation of children from Ukraine, claimed Russia never opposed reuniting children with their families.

Qatar's foreign ministry issued a statement saying it had been involved in recent family reunifications through its embassy in Moscow but it provided no details.