Russia has resorted to a “terrorist campaign” against the civilian population of Ukraine after failing to achieve the strategic, operational and tactical goals of its invasion, the top US general said on Wednesday.

However, Ukraine is unlikely to be able to militarily force Russia out of all areas it occupies, but a winter slowdown in fighting could create an opportunity for a political settlement, General Mark Milley told a news conference.

Russia is forcing “a campaign of terror, a campaign of maximum suffering, on Ukrainian civilians in order to weaken Ukrainian morale,” he said.

Many of Russia’s recent attacks – including a barrage of dozens of missiles over Ukraine on Tuesday, which Milley said may have been the worst of the war – have targeted the country’s energy infrastructure.

“Deliberately attacking the civilian power grid, causing undue collateral damage and unnecessary suffering to civilian populations, is a war crime,” Milley said.

Moscow’s attacks on infrastructure, which Milley said will likely lead to a harsher winter in Ukraine, came after a series of Russian failures to achieve its military goals in the country.

“Ukrainians have achieved success after success. And the Russians failed every time. They lost strategically, they lost operationally, and I repeat, they lost tactically,” the general said.

Russia has failed in its goal of overthrowing President Volodymyr Zelenskyy and his government, as well as more limited goals like conquering the Donbass region, Milley said.

“The strategic realignment of their objectives, the illegal invasion, have all failed – every single one of them,” he said.

At the same time, Moscow controls about 20 percent of Ukraine, and Kiev’s troops are unlikely to force the Russians to leave the country any time soon.

“The likelihood of a Ukrainian military victory, defined as kicking the Russians out of all of Ukraine… the likelihood of that happening in the foreseeable future is not high,” Milley said.

But there is a tendency for fighting to ease in the winter months and this could provide an opportunity for talks.

“If there is a slowdown in actual tactical combat, that may become a window … for a political settlement, or at least for talks to begin to initiate a political settlement,” Milley said.

“The Russian military is really, really badly off. So you want to negotiate at a time when you are at your strength and your opponent is suffering from weakness,” he added.

US Secretary of Defense Lloyd Austin, alongside Milley, said support from Ukraine’s allies is likely to give Kiev’s troops an advantage next winter.

“We’ve pushed … tremendous amounts of winter gear into Ukraine thanks to countries like Canada and others that have been really, really generous,” Austin said.

Russia, meanwhile, is fighting in a foreign country and is facing attacks on its supply lines, meaning it will have a hard time procuring the equipment its troops need.

“I think the Ukrainians will have the upper hand in this fight like they have right now” and “they will have that upper hand in the winter,” said Austin.