Fighting in eastern Ukraine reportedly leaves 22 civilians dead

At least 22 civilians were killed Tuesday by shelling in two conflict-stricken cities in eastern Ukraine, local authorities said.

The use of unguided rockets in fighting between government forces and pro-Russian separatist rebels has been taking a noticeably heavier toll in recent weeks and been criticized by rights groups.

With turmoil raging across a wide swathe of the region, international investigators were again prevented Tuesday from visiting the site of the Malaysia Airlines jet shot down earlier this month.

City hall in Luhansk, which is controlled by separatist rebels, said Tuesday that five people were killed when an old people's home was struck by artillery fire. Russian television showed images of bodies in wheelchairs covered with blankets.

Ukraine security spokesman Andriy Lysenko said that rebels had blocked the railroad out of Luhansk, barring residents from leaving the city.

"If we were earlier able to organize additional trains to and from Luhansk, to Kiev, now they have completely blocked the railway line," Lysenko said.

Lysenko also accused separatist fighters of using children as human shields and stopping cars from leaving Luhansk. It was not immediately possible to confirm those claims.

In Horlivka, a city besieged by government troops, the mayor's office reported 17 people, including three children, dying as a result of shelling.

The mayor's office said there has been major damage to many homes and government offices in the center of the city. It also said the top floor of a school was destroyed as a result of direct hit from a shell.

Rebels accuse the government of indiscriminately using heavy artillery against residential neighborhoods in areas under their control.

A U.N. monitoring mission in Ukraine says there has been an alarming buildup of heavy weaponry in civilian areas of Donetsk and Luhansk — including artillery, tanks, rockets and missiles that are being used to inflict increasing casualties and damage to civilian infrastructure.

The U.N. said in a report this week that use of such weaponry could amount to a violation of international humanitarian law.

"There is an increase in the use of heavy weaponry in areas that are basically surrounded by public buildings," said Gianni Magazzeni, head of the U.N. office's branch that oversees Ukraine. "All international law needs to be applied and fully respected."

Ukraine's government has stated that it has banned use of artillery in heavily resided areas and in turn accuses separatists of targeting civilians in an effort to discredit the army.

The overall death toll has been steadily rising. The U.N. has said that at least 1,129 people were killed between mid-April, when fighting began, and July 26.

Ukrainian troops have for several days encroached on the outskirts of Horlivka, which is just north of the regional center and the main rebel stronghold, Donetsk.

Heavy fighting has also spread to other areas in the region, including towns not far from the crash site of the Malaysia Airlines Flight 17.

Lysenko said Tuesday that 10 soldiers were killed and another 55 wounded in fighting over the past day.

A team of Dutch and Australian police officers and forensic experts is currently stationed in Donetsk in the hope of traveling to the fields where the Boeing 777 came down.

For the third day running, the delegation has been forced to cancel plans to travel to the area of the wreckage.

There were also signs of the conflict spreading into Donetsk, which had so far only seen serious fighting only on its fringes.

A blast heard in the city center at lunchtime prompted members of the international police team sitting in their hotel restaurant to quickly seek shelter inside the building. It was not clear what caused the explosion.