DONETSK, Ukraine — A rebel-held city in eastern Ukraine came under intensified shelling Wednesday as the U.N. revealed that the death toll from the fighting between government troops and separatists has nearly doubled in the last two weeks.

A spokeswoman for the U.N.’s human rights office, Cecile Pouilly, said the organization’s “very conservative estimates” show the overall death toll has risen to at least 2,086 people as of Aug. 10, up from 1,129 on July 26.

Pouilly said at least 4,953 others have been wounded in the fighting since mid-April.

While the humanitarian crisis reaches critical stage in at least one major Ukrainian city, trucks apparently carrying some 2,000 tons of aid have lain idle at a military depot in Russia. Moscow insists it coordinated the dispatch of the goods, which range from baby food and canned meat to portable generators and sleeping bags, with the international Red Cross, but Ukraine says it’s worried the mission may be a cover for an invasion.

A spokesman for local authorities in the main rebel-controlled city of Donetsk told The Associated Press on Wednesday that rocket attacks over the previous night had increased in intensity.

Associated Press reporters saw two bodies lying in a street Wednesday morning in Donetsk’s southwestern Petrovsky district. The local government said three were killed, a figure that adds to the sharply mounting death toll.

Shelling in Donetsk has damaged power plants and gas pipelines, leaving large parts of the city without electricity or gas, city council spokesman Maxim Rovinsky said.

Damage to residential buildings is an apparent result of two combined factors: The army has refrained from going into Donetsk, favoring an artillery campaign of attrition over close urban combat. And local residents have regularly revealed that damaged houses are often to be found near rebel firing positions, suggesting that the rocket attacks are responses to outgoing strikes.

Government troops and the volunteers fighting with them are also sustaining heavy losses while making regular territorial advances.

At least 12 militiamen fighting alongside the army were killed overnight Tuesday in an ambush outside Donetsk, a spokesman for their radical nationalist movement said Wednesday.

The situation in Luhansk, also in rebel hands, is yet more serious. City authorities said Wednesday they had entered the 11th straight day without power supplies. Running water has dried up and rocket attacks remain a daily occurrence.