MINSK, Belarus — Guns would fall silent, heavy weapons would pull back from the front andUkraine would trade a broad autonomy for the east to get back control of its Russian border by the end of 2015 under a peace deal hammered out Thursday in all-night negotiations between Russia, Ukraine, France and Germany.

The deal was full of potential pitfalls that could derail its implementation, however. In announcing the plan, Russia and Ukraine differed over what exactly they had agreed to in the marathon 16-hour talks, including the status of Debaltseve, a key town now under rebel siege.

Russian President Vladimir Putin told reporters that the agreement envisages a cease-fire beginning Sunday (2200 GMT (5 p.m. EST) Saturday) as well as a special status for Ukraine’s separatist regions and provisions to address border concerns and humanitarian issues.

Ukrainian President Petro Poroshenko said there was no agreement on any autonomy or federalization for eastern Ukraine, a longtime demand of Russia, which wants that to maintain its leverage overUkraine and prevent its neighbor from ever joining NATO.

The deal, however, requires the Ukrainian parliament to give wide powers to the eastern regions as a condition for restoring Ukraine’s full control over its border with Russia — a provision certain to trigger heated debate in Kiev.

Uncertainty remained even on the cease-fire, as Putin admitted he and Poroshenko disagreed on the situation at the government-held town of Debaltseve.

“We now have a glimmer of hope,” said German Chancellor Angela Merkel, who brokered the talks in the Belarusian capital of Minsk together with French President Francois Hollande. “But the concrete steps, of course, have to be taken. And we will still face major obstacles. But, on balance, I can say what we have achieved gives significantly more hope than if we had achieved nothing.”

More than 5,300 people have died since April in eastern Ukraine amid fighting between the Russian-backed separatists and government troops. Battles still raged Thursday even as the four leaders held peace talks.

The new deal envisages a 50- to 140-kilometer (31- to 87-mile) wide buffer zone as both parties pull back heavy artillery and rocket systems from the front line, depending on their caliber. The withdrawal should begin no later than the second day after the cease-fire becomes effective and should be completed within two weeks.

In a win for Ukraine, the rebel regions, which held their own elections last fall that Ukraine and the West declared a sham, are obliged to hold a new local vote under the Ukrainian law.