“There is no doubt that summary killings and atrocities are being committed by both pro-Russian separatists and pro-Kiev forces in eastern Ukraine, but it is difficult to get an accurate sense of the scale of these abuses,” John Dalhuisen, Europe and Central Asia Director at Amnesty International, said in a press release.

“It is likely that many have not yet been exposed and that others have been deliberately misrecorded. It is also clear that some of the more shocking cases that have been reported, particularly by Russian media, have been hugely exaggerated.”

Amnesty’s report, “Summary killings during the conflict in eastern Ukraine,” presents findings from research conducted in Donbass, in eastern Ukraine, in late August and September.

Russian media on Sept. 23 reported that mass graves had been discovered in the Donetsk Region while it was under the control of Ukrainian armed forces. Russian Foreign Minister Sergei Lavrov was reported as saying that over 400 bodies had been found in the graves.

But Amnesty researchers, who were on site by Sept. 26 found evidence of only four extrajudicial killings that pro-Kiev forces had carried out. They were buried in two graves near the village of Komunar. Five additional bodies in a single grave nearby were found to be pro-Russian separatist fighters.

The report added that pro-Russian groups had carried out execution style killings of detainees since the start of the conflict, with victims including pro-Ukraine activists and suspected Kiev sympathizers.

A businessman in southeastern Ukraine who was detained for suspected links with the Batkivshchyna party told Amnesty, “At 4:30am a fighter woke us, shouting, ‘Up. Evacuation.’ They opened three or four cell doors, and in all I heard six to eight gunshots. It was like roulette — some were shot, some released, some taken away.”

The United Nations has estimated that more than 3,700 people have been killed in fighting in Ukraine since the conflict began.

The biggest single loss of life to date has been the downing of flight MH17 in July, which resulted in the death of 298 passengers and crew. That incident is being investigated by the German Federal Prosecutor’s office, an office spokesman said Sunday.

Evidence so far shows that pro-Russian rebels were responsible for shooting a missile that caused MH17 to crash, Germany’s foreign intelligence service, the Bundesnachrichtendienst (BND), said according to a report in Der Spiegel on Sunday.

The BND said it had completed a detailed enquiry into the July 19 incident. Agency chief Gerhard Schindler presented findings to members of the country’s parliamentary control committee on Oct. 8. It the briefing he provided satellite images and photo evidence indicating pro-Russian separatists had captured a BUK air defense missile system from a Ukrainian military base that was responsible for the crash.

“It was pro-Russian separatists,” Schindler said, adding that four German citizens died in the crash, according to the report.

The conflict in eastern Ukraine followed February anti-government protests in Kiev’s Maidan Square over ousted president Viktor Yanukovych’s perceived reluctance to follow through with plans to establish closer relations with the European Union. Mass protests in the capital led to the deaths of dozens and served to polarize Ukrainians along pro-Russian and pro-Europe Union lines.

Fighting erupted in eastern Ukraine after pro-Russian separatists occupied local administration buildings and security services installations in the Donetsk and Luhansk regions in April and May, after Russia annexed the Crimean peninsula. Ukrainian forces then embarked on what it called an anti-terrorism operation and a ceasefire agreement signed on Sept. 5 did not stop the fighting.

A large explosion at a munitions factory rocked the rebel-held city of Donetsk on Monday. There were no reported casualties. A Ukrainian military spokesman told Reuters Kiev was not behind the blast, located in the city's northeast, what has been a stronghold for the separatists.

With wire services