Donetsk, AP—Government troops fought to gain control of the rebel-held city of Donetsk and a key highway in eastern Ukraine on Wednesday, in battles that left 34 residents and nine troops dead in just 24 hours, authorities said.

The Ukrainian troops are trying to encircle Donetsk, the largest city still in rebel hands, and also drive the rebels out of the city of Luhansk. Several neighborhoods in Donetsk have been hit with artillery fire in the last few days and fighting on the outskirts has become more intense.

The Kiev-backed administration in Donetsk quoted a death toll of 34 local residents killed and 29 wounded as of noon Wednesday, a figure it said did not include any government troops.

Earlier, a Ukrainian official said nine troops were killed and 22 wounded in overnight fighting in Ilovaysk, a town near Donetsk, as the government sought to retake a major railroad and a highway that leads to Russia.

Andriy Lysenko, spokesman for the Ukrainian National Security Council who gave that toll, said fighting continued in Ilovaysk on Wednesday even though government forces have gained overall control over it.

Among those killed in Ilovaysk was a Ukrainian-American known by the nom de guerre of “Franko,” said Anton Herashchenko, an adviser to the interior minister. He said Franko was an American citizen with a military background who had been living in eastern Ukraine for the past 10 years and obtained Ukrainian citizenship before joining the battalion.

For several weeks running, Donetsk has come under sustained shelling from all sides. The imprecision of the shelling is creating much animosity while seemingly taking a limited toll on rebel forces.

On Wednesday morning, rockets slammed into residential areas, including the suburb of Makiivka.

“I was with my grandmother in the bathroom, because there is a bearing wall in there,” said Anna Zyukova, 22. “And then all of sudden, bam-bam.”

Many residents have been taking refuge in improvised bomb shelters in apartment building basements. Residents in Makiivka huddled in groups near one such shelter Wednesday, chatting and listening as rockets flew in and out several miles away.

At a rebel camp by a checkpoint closer to the fighting, a rebel commander who identified himself only as “Chaika”—Russian for seagull—said he was at a loss to explain why army shells were hitting apartments.

“We purposely don’t take up positions where people live,” he said—a claim that Ukrainian officials have repeatedly dismissed.

The situation in the besieged city of Luhansk, a rebel stronghold just 12 miles (20 kilometers) from the Russian border, also remained critical Wednesday as the government and rebels fought running battles in city streets, local authorities said.

Luhansk has been without electricity, running water or phone connections for 18 days, and residents are reported to be standing in lines to buy bread baked on portable generators as food grows scarce.

The Kiev government also has pursued diplomatic efforts to resolve the conflict, which the United Nations says has killed more than 2,000 people and displaced over 340,000 since fighting began in mid-April.

Ukrainian President Petro Poroshenko will host German Chancellor Angela Merkel this weekend in Kiev before meeting next week with Russian President Vladimir Putin in Minsk, the capital of Belarus.

Ukraine has accused Russia of arming and supporting the rebels, a charge that Russia denies. The fighting began a month after Russia annexed Ukraine’s Black Sea peninsula of Crimea.

In Moscow on Wednesday, protesters scaled one of the city’s famed Stalin-era skyscrapers and painted the Soviet star on its spire in the national colors of Ukraine. They also attached a yellow-and-blue Ukrainian flag to the top of the 580-foot (176-meter) building.

While Moscow police detained four suspects and charged them with vandalism, a crime punishable with up to three years in prison, Poroshenko, the Ukrainian president, welcomed the flag-hoisting over the skyscraper in a video message, calling it a “symbolic” gesture.