Refugees from eastern Ukraine line up in a camp to get food in a refugee camp near Donetsk. (Dmitry Serebryakov/AFP/Getty Images)

Ukraine on Monday accused pro-Russian separatists of killing dozens of civilians in an attack on a convoy fleeing a besieged rebel-held city. The rebels denied that any attack occurred, while the United States confirmed an attack but said it did not know who shelled the convoy.

The war zone in eastern Ukraine is effectively off-limits to journalists and lacks power in many places, limiting residents from easily providing reports. All this makes independent verification difficult.

Fighting between government troops and separatists in Ukraine has forced nearly 350,000 people to flee their homes, according to the United Nations. The flow of refugees from eastern Ukraine has been rising steadily as the humanitarian situation in rebel-held cities deteriorates. Running water and electricity have been cut off completely in many rebel-held cities or are getting more limited by the day.

The rebels shelled the refu­gee convoy Monday morning between the towns of Khryashchuvate and Novosvitlivka with Grad rockets and other weapons imported from Russia, Col. Andriy Lysenko, a spokesman for Ukraine’s National Security and Defense Council, told reporters.

The towns lie on the main road that connects the besieged city of Luhansk to Russia.

Scores of refugees have fled the fighting in Ukrainian cities Donetsk and Luhansk to camps across the border in Russia. (Reuters)

“Many people were killed, among them women and children,” Lysenko said. “We are not able to count the death toll at this point.”

When asked about a rough estimate of deaths, he said “dozens.”

Oleksiy Dmytrashkivsky, a spokesman for the government’s military operation in the east, later said that 15 bodies had been recovered from the smoldering vehicles and that service members were collecting the body parts of at least 10 more people.

However, Alexander Zakharchenko, the rebel chief in the separatist stronghold of Donetsk, insisted that no such attack had taken place. His deputy, Andrei Purgin, said he had no information about an attack and insisted that his forces would never have been involved.

“If someone was killed, it wasn’t us but the Ukrainian military,” Purgin said.

The road where Ukraine said the attack occurred had been targeted previously by government forces, Purgin said.

That same road to Luhansk would probably be taken by a controversial Russian aid convoy if the Kiev government allows it into the country.

The United States offered condolences to the families of those killed Monday.

“We strongly condemn the shelling and rocketing of a convoy that was bearing internally displaced persons in Luhansk and express our condolences to the families of the victims,” State Department spokeswoman Marie Harf told reporters in Washington. “All sides must take every precaution to protect innocent lives. We are unable to confirm reports of who was responsible for the shelling and rocketing.”

Residents have been fleeing eastern Ukraine amid a worsening humanitarian situation. Residents in Luhansk have had no running water, power or phone connections for 16 days. Basic foods are in short supply, city hall said Monday, adding that fighting continues in and around the city.

In Donetsk, the largest city in rebel hands, several houses were hit by artillery fire over the weekend in the Budyonovsky district, which stands next to a rebel encampment.

Tensions have been high in the past week as Russia decided to send an aid convoy to help those in rebel-held areas of eastern Ukraine.

The more than 200 trucks, parked in a Russian field by the border, have been watched with suspicion by Ukraine and the West, especially as Ukrainian forces have been winning back significant territory from the rebels in the past few weeks. Ukraine suggests that Russia could use the aid convoy to send help to the separatists — or to delay the Kiev government’s advances with an opportune cease-fire.

The International Committee of the Red Cross, which is expected to take responsibility for the Russian convoy when it enters Ukraine, said Monday that it is still waiting for security guarantees from all sides for the mission into eastern Ukraine.

Russia’s foreign minister, meanwhile, said in Berlin that he expects the Russian aid convoy to enter Ukraine in the near future.

— Associated Press