Artemivsk, Ukraine, AP—Russian-backed separatists mounted a vicious assault Friday in eastern Ukraine ahead of a weekend ceasefire deadline, pummeling a strategic railway hub with wave upon wave of shelling in a last-minute grab for territory. At least 26 people were killed across the region.

The fiercest confrontations focused on the government-held town of Debaltseve, a key transport center that has been on the receiving end of dozens of artillery and rocket salvos in the 24-hour period after the peace deal was sealed Thursday by the leaders of Russia, Ukraine, Germany and France.

Associated Press reporters observed intense shelling Friday along the highway north of Debaltseve, which remains the town’s only land link with the rest of government-controlled territory.

The deadline for the warring sides to halt hostilities is Sunday at one minute after midnight. Interfax-Ukraine news agency quoted Petro Mekhed, Ukraine’s deputy defense minister, as saying that separatist forces had been tasked with hoisting their flags over Debaltseve, as well as the key port city of Mariupol, before the ceasefire takes hold.

Military spokesman Andriy Lysenko said 11 soldiers have been killed and 40 wounded across eastern Ukraine since the agreement was reached in the Belarusian capital, Minsk. At least eight civilians also have died in government-controlled territory, regional authorities loyal to Kiev said, while the rebels said seven civilians were killed in artillery attacks on the separatist-held cities of Luhansk and Horlivka.

Shells landed Friday as far as Artemivsk, a government-held town 25 miles behind the front line. Associated Press reporters saw the body of a child killed after rocket fire hit a kindergarten there, and regional officials said the child and one other civilian died in the attack.

In recent days, separatist fighters have nearly completely encircled Ukrainian forces in Debaltseve, where all but a few thousand civilians have fled the fighting.

Ukraine says Debaltseve should remain in government control under the terms of a September peace deal. A copy of that agreement leaked to Ukrainian media shows the town lying on the government’s side of the line of division agreed by both the rebels and Ukrainian officials.

But even as Thursday’s peace deal was announced, Russian President Vladimir Putin and Ukrainian President Petro Poroshenko appeared to disagree over the town’s future. Putin said the rebels consider the Ukrainian forces there surrounded and expect them to surrender, while Ukraine insisted its troops have not been blocked.

On Friday, Ukrainian access to the sole highway linking Debaltseve to government-held territory looked to have been compromised with the apparent capture of Lohvynove, a village just to the north. AP reporters on Friday saw the smoldering remains of two Ukrainian army trucks on a road nearby.

The Donbass Battalion, a unit with Ukraine’s National Guard that is engaged in battles around Lohvynove, said in a statement that captured combatants had confirmed that Russian troops were actively involved in the battles.

Moscow vehemently denies that it provides manpower and weapons to the rebel forces, but the sheer quantity of powerful weapons at the separatists’ disposal belies that assertion.

Russian state news agency RIA-Novosti quoted Kremlin spokesman Dmitry Peskov as saying Friday that Moscow would act only as a guarantor in the peace process, and could not affect developments on the ground.

“We simply cannot do this physically, because Russia is not a participant in this conflict,” Peskov was quoted as saying.

Meanwhile, Russia circulated a draft resolution Friday in the United Nations Security Council endorsing the agreement and calling on all parties involved to carry it out. The Council is expected to vote on the resolution Sunday, hours after the ceasefire is to take effect.

Elsewhere, by the Azov Sea in southeastern Ukraine, government troops said they had retaken a handful of villages. Troops there have denied reporters access to those operations, which aim to push rebel fighters back from the government-held port of Mariupol.

The Ukraine ceasefire is to be monitored by the Organization for Security and Cooperation in Europe’s observer mission in Ukraine. OSCE Secretary General Lamberto Zannier said in Kiev that he hoped hostilities would be halted by the deadline.

“We would really hope to see a decrease already between now and that moment,” he said.
Zannier said that combatants would have to do more to enable the OSCE peace-monitoring mission, which makes ample use of drone cameras, to properly fulfil its mandate.
“Aerial vehicles have been targeted more than once, monitors have been taken hostage, so we need a change of attitude,” he said.

The next step after the ceasefire is to form a sizeable buffer zone between Ukrainian forces and Russia-backed rebels. Each side is to pull heavy weaponry back from the front line, creating a zone roughly 30-85 miles wide, depending on the caliber of the weapons. The withdrawals are to begin Monday and be completed in two weeks.

Other thorny political questions, including a degree of autonomy for the disputed eastern regions, are to be settled by the end of the year.

The peace deal envisions an amnesty for people involved in the conflict, but the vague terms of that provision will likely provoke further disagreements. Speaking to parliament, Ukrainian Foreign Minister Pavlo Klimkin said amnesty would not be granted to anyone suspected of committing crimes against humanity.

“This is an absolute position that was unambiguously underlined during negotiations,” Klimkin said.