International observers turned back Wednesday after making another attempt to reach the site where Malaysia Airlines Flight 17 went down in eastern Ukraine, and a government official said the area near the zone had been mined by pro-Russian separatists who control it.
Observers from the Organization for Security and Co-operation in Europe set out Wednesday in two vehicles – without frustrated crash investigators from the Netherlands who have been trying to reach the site for four days.
But the OSCE observers turned back to the city of Donetsk after discussions with rebels.
Safety concerns and hindrance from the separatists who control the area have kept the investigation team away. Foreign governments whose citizens died have complained the site is not secured and some human remains have not been recovered.
Government security spokesman Andriy Lysenko added to those concerns Wednesday by saying separatists "have mined the approaches to this area. This makes the work of the international experts impossible."
Lysenko was asked at a briefing about concerns that Ukrainian efforts to win back territory were increasing fighting in the area and slowing access. He said that Ukrainian troops weren't conducting operations against the separatist near the site, but were trying to cut off their supply lines to force them to leave the area.
Elsewhere, Ukrainian forces took control of the town of Avdeevka, just to the north of the rebel stronghold of Donetsk.
Local officials said fighting over the past 24 hours killed 19 people in the region.