AVDIIVKA, Ukraine -- Freezing and nerve-shattered residents of an eastern Ukraine town battered by an upsurge in fighting between troops and Russia-backed rebels flocked to a humanitarian aid center Wednesday to receive food and warm up.

Heavy shelling of government-held Avdiivka, just north of the rebel stronghold city of Donetsk, began over the weekend and persisted into early Wednesday. Donetsk city also was hit.

At least 10 people have been killed since Monday and dozens wounded.

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Separatist rebels have been fighting government troops and volunteer brigades in eastern Ukraine since April 2014 in a conflict that has killed more than 9,700 people. A pact reached nearly two years ago in Minsk, Belarus, called for a cease-fire, for heavy weapons to be pulled back from the front lines and for a political resolution of the conflict, but the agreement has been observed only fitfully and skirmishes and artillery fire have persisted.

In a worrisome sign, an Associated Press reporter saw rebel artillery positions in the center of Donetsk city on Wednesday.

What sparked the recent escalation is unclear. But each side could find negotiation benefits in it.

The Ukrainian government -- concerned that the new Trump Administration might take a comparatively soft line on Russia, and possibly change the long-held American stance on the NATO alliance -- could point to the escalation as evidence that Russia cannot be trusted.

That prospect was acknowledged by President Vladimir Putin’s foreign affairs adviser Yuri Ushakov. “Kiev is trying to use the fighting it provoked itself as a pretext to refuse to observe the Minsk agreement and blame Russia,” he told reporters Wednesday.

But by showing the strength of the rebels and their Russian backers, the fighting could send a signal to Washington that Moscow holds power in the region and the United States should offer concessions to Moscow if it wants peace in Ukraine.

The escalation “seems to be another reason for the soonest possible resumption of dialogue and cooperation between Russia and America,” Kremlin spokesman Dmitry Peskov said.

NATO Secretary General Jens Stoltenberg, meanwhile, urged Russia to use its “considerable influence” with the rebels to stop what he called “the most serious spike in violations” of the strained ceasefire to date.

Stoltenberg told reporters the ceasefire had been violated at least 5,600 times in recent days, cutting off electricity to about 20,000 as the temperatures plunged.

In the late morning Wednesday, shelling subsided; there were unconfirmed reports the sides had agreed to a cease-fire to restore electricity and water supplies.

The power outage hit amid a strong cold snap, with temperatures in Avdiivka as low as minus 18 Celsius (0 Fahrenheit). Hundreds of city residents streamed to a stadium where aid agencies were distributing food, and to warming stations.

The Ukrainian government’s press office for the military operation in the east reported one soldier killed, and nine soldiers and one civilian injured late on Tuesday.

In Makiivka, the rebel-controlled northeastern suburb of Donetsk, two coal miners were injured Wednesday morning by shelling as they were walking to work, the rebels’ Donetsk News Agency reported.

An Associated Press reporter outside Avdiivka saw a transporter carrying Grad multiple missile launcher with empty rounds drive away from the front line Wednesday.

Grad is among the heavy weaponry that both warring parties committed to pull back when they signed a cease-fire agreement in Minsk in 2015.

In Donetsk, local residents reported incessant outgoing and incoming artillery salvos heard throughout the night and in the morning, an intensity that the city has not seen in months.

The so-called Contact Group of Russia, Ukraine and the Organization for Security and Cooperation in Europe, which aims at implementing the two-year-old peace pact, was meeting Wednesday in Minsk, but there were no immediate reports of developments.