KIEV, Ukraine — Ukrainian government forces recaptured three towns from pro-Russia separatists and were pressing toward the Malaysia Airlines crash site in eastern Ukraine where the separatists accused of downing the plane have obstructed international disaster investigators, officials said Monday.
The United Nations high commissioner for human rights, meanwhile, said at a news conference in Geneva that the shooting down of MH-17 and the deaths of all 298 people on board were being investigated for possible war-crime charges.
Pro-Russia militants who seized a dozen towns and cities in eastern Ukraine in March and April have seen the territory under their control reduced by more than half during the past few weeks and are now holed up in their embattled strongholds of Donetsk and Luhansk. The separatists also control the miles-wide crash site strewn with debris and victims’ remains but face an advancing government offensive emboldened by international outrage over the plane’s destruction.
Andriy Lysenko, a spokesman for Ukraine’s National Security and Defense Council, told journalists in Kiev on Monday that government troops had recovered control of Shakhtarsk, about 20 miles from the center of the crash site.
“Our troops entered Shakhtarsk, Torez and Lutuhyne,” Lysenko said, claiming government control of towns on roads leading to the wreckage strewn among sunflower fields.
A team of more than 60 Dutch and Australian investigators attempted to reach the crash site for a second time Monday but stopped short because of fighting nearby, a spokesman for the Organization for Security and Cooperation in Europe told reporters in Kiev.
The international police team is charged with securing the debris field near the village of Hrabove but has been prevented from reaching the area by fighting and militants’ roadblocks since the July 17 disaster.
U.S. intelligence sources have identified the cause of the crash as a surface-to-air missile launched by a sophisticated BUK anti-aircraft system allegedly provided to the separatists by Russia.
U.S. and European Union officials have accused Russian President Vladimir Putin of arming the separatists and instigating them with his late February seizure of Ukraine’s Crimean peninsula and annexation of the militarily strategic region to Russia. Much of the eastern Ukraine territory occupied by the pro-Russia militants would provide a land bridge for Russia toward Crimea, which hosts Russia’s naval fleet but has no border with the Russian mainland.
Putin denies responsibility for the separatists’ actions, although many of those killed in battles with Ukrainian forces have been identified as Russian citizens and Russian special forces veterans openly command the militants in the Donetsk and Luhansk regions.
The European Union is expected to vote this week on a proposal for tough new sanctions that would target key sectors of the Russian economy, including banking, oil and defense. The U.S. has led a campaign to impose harsh penalties on the Russian economy to force the Kremlin to change its policies in Ukraine and halt alleged support for the separatists.
The Russia-allied militants located the downed plane’s black boxes and held them for several days before turning them over to investigators led by the Netherlands, which lost 193 citizens in the crash.
Lysenko said the Ukrainian government had been informed that an initial review of the black-box data suggested the crash was caused by shrapnel puncturing the fuselage, causing massive decompression and breakup of the Boeing 777 that had been flying at an altitude of more than 33,000 feet.
The flight from Amsterdam en route to Kuala Lumpur, the Malaysian capital, was carrying more than 100 passengers destined for an international AIDS conference in Australia, including 28 Australians.
Australian Foreign Minister Julie Bishop was in Kiev on Monday to discuss Ukrainian government support for an armed Australian police force to protect the crash site and foreign investigators trying to collect evidence from the scene.
“We’ll be seeking assurances that any military action doesn’t compromise our humanitarian mission,” Bishop told a news conference.
Bishop also said Australia hoped Russia would use its influence with the rebels to ensure access to the site so that investigators can determine responsibility for disaster.
In Geneva, a U.N. report released Monday said the eastern Ukraine conflict spurred by pro-Russian militants’ land grabs four months ago has claimed the lives of 1,129 people.
U.N. High Commissioner for Human Rights Navi Pillay said the Malaysia Airlines jet crash was being investigated as a possible war crime and called for immediate and unhindered access for investigators to the crash site.
“This violation of international law, given the prevailing circumstances, may amount to a war crime. It is imperative that a prompt, thorough, effective, independent and impartial investigation be conducted into this event,” Pillay said.
She said all those responsible for the killings, detentions and rights abuses would be identified and brought to justice.
Pillay urged all sides “to bring to an end the rule of the gun and restore respect for the rule of law and human rights.”