Russian shelling killed at least five people and wounded 13 others during the previous 24 hours, Ukrainian authorities said Monday, as the Kremlin’s and Kyiv’s forces remained locked in combat in eastern Ukraine ahead of renewed military pushes that are expected when the weather improves.

The casualties included a woman who was killed and three others who were wounded by the Russian shelling of Kharkiv, Ukraine’s second-largest city in the country’s northeast, according to regional Gov. Oleh Syniyehubov.

Moscow’s troops seized large areas of the northeastern Kharkiv region in the months following its invasion of its neighbor last February. But Ukrainian counteroffensives that began in August snatched back Russian-occupied territory, most notably in Kharkiv.

Those successes lent weight to Ukraine’s arguments that its troops could deliver more stinging defeats to Russia if its Western allies provided more weaponry.

Kyiv last week won promises of tanks from the United States and Germany to help its war effort.

Poland’s Prime Minister Mateusz Morawiecki on Monday hinted at the prospect of more upcoming pledges, saying that “any activity aimed at strengthening Ukraine’s defense powers is under consultation with our NATO partners.”

Such a move could encounter some familiar political obstacles, however.

Chancellor Olaf Scholz, after demurring for weeks over sending Germany’s Leopard 2 tanks to Ukraine, looks set to dig his heels in over providing fighter jets.

Scholz, who is currently on a trip to South America, said he regretted the emergence of the fighter jet discussion.

He said in Chile on Sunday that a serious debate is necessary and not a “competition to outdo each other … in which perhaps domestic political motives are in the foreground rather than support for Ukraine.”

Military analysts say more aid for Ukraine is crucial if Kyiv is to block an expected Russian offensive in the spring and launch its own effort to push back the Russian forces.

“The pattern of delivery of Western aid has powerfully shaped the pattern of this conflict,” the Institute for the Study of War, a U.S.-based think tank, said late Sunday.

As Ukraine emerges from a bitter winter, attention is turning to the possibility of new offensives when the weather improves.

The British Ministry of Defense noted Monday that the Kremlin never formally rescinded last September’s order for a partial mobilization of reservists that boosted troop numbers for combat in Ukraine. It said Russia may be keeping the door open for further call-ups.

“The Russian leadership highly likely continues to search for ways to meet the high number of personnel required to resource any future major offensive in Ukraine, while minimizing domestic dissent,” it said in a tweet.

Kremlin spokesman Dmitry Peskov insisted that supplies of Western weapons won’t stop Russia.

“Ukraine keeps demanding new weapons and the West is encouraging those demands,” Peskov said in a conference call with reporters Monday. “It’s a deadlock, it results in a significant escalation and makes NATO countries increasingly involved in the conflict.”

Ukraine’s presidential office said the eastern Donetsk region, which has been the scene of intense fighting for months, remains “invariably hard.”

Heavy fighting continued to rage around Bakhmut and Vuhledar, with regional Gov. Pavlo Kyrylenko saying that 15 towns and villages in the region came under shelling Sunday.

Russian forces have been trying for months to capture Bakhmut, with the effort being led by the Wagner Group, a private military company led by a rogue millionaire with longtime links to Russian President Vladimir Putin.

Ukrainian troops last week said they conducted an organized retreat from Soledar, a few kilometers (miles) from Bakhmut, amid pressure from Wagner, which is believed to have a large number of convicts in its ranks.

Ukrainian authorities said the southern city of Kherson also has come under Russian shelling. The bombardment damaged residential buildings, a hospital, a school, a bus station, a bank and a post office.

Two foreign vessels were damaged in the port of Kherson, the presidential office added without elaborating.