KHARKIV, Ukraine — Trying again to recover the last bodies from the crash site of a downed Malaysian airliner, about 30 unarmed Dutch police officers left this eastern Ukrainian city Sunday for the debris-strewn site but decided to put off the mission because of intense fighting in the area.
The Malaysian government struck a deal with pro-Russia rebels to give the Dutch investigators access to the area. After traveling by road to Donetsk, a rebel stronghold 190 miles south of Kharkiv, however, the Dutch team turned back, a spokeswoman for the Organization for Security and Cooperation in Europe said.
Small groups of foreign police and forensic experts have managed to reach the area where the Malaysia Airlines Boeing 777 crashed on July 17, but efforts to secure the site with larger contingents have repeatedly fallen through.
The area where Flight 17 came down is tactically important for the Ukrainian military, which is attempting to close access from the east to the provincial capital, Donetsk, a rebel stronghold.
The objective is to keep separatists in the city from being resupplied and reinforced from the direction of the Russian border.
Ukraine’s National Security Council said Sunday that government troops have encircled Horlivka, a rebel-held town about 20 miles north of Donetsk, the Associated Press reported. A representative of the separatist military command in Donetsk confirmed that there had been fighting in Horlivka but said that rebel fighters were holding their positions.
Elsewhere, Russian state news agency RIA Novosti reported Sunday a column of Ukrainian armored personnel carriers, trucks, and tanks had entered the town of Shakhtarsk, 10 miles west of the crash site.
The prospects for a more robust foreign presence at the plane debris field had initially improved Sunday when Prime Minister Najib Razak of Malaysia reached an agreement with a leader of the rebels, Alexander Borodai, “to allow a deployment of international police personnel to enter the crash site,” Najib’s office said in an e-mail.
Australia said Sunday it also plans to send unarmed police officers to the crash site as part of an international push to prevent any further meddling with human remains and evidence scattered over rebel-controlled farmland.
Debris from the crash is scattered among wheat and sunflower fields. The site remains unguarded despite growing reports of tampering with the plane wreckage and passenger items.
Monitors from the OSCE reported after a visit to the site Friday that parts of the wreckage had been moved and that pieces of hand luggage had been unzipped and left empty.
“Our objective is to get in, to get cracking, and to get out — that’s our objective,” Prime Minister Tony Abbott of Australia told a news conference in Canberra, the capital. Australia had considered allowing some of its men to carry weapons, but Abbott indicated he had decided against that.
The jet crashed in territory in eastern Ukraine held by pro-Russia rebels, and although most of the bodies of the 298 victims have been recovered and flown to the Netherlands for identification, forensic investigators have not been able to reach the area in sufficient numbers to ensure that all the bodies have been found.
They also want to collect debris that could provide evidence of who brought the plane down. The Netherlands, whose citizens accounted for around two-thirds of the crash victims, is leading an international effort to get to the bottom of what happened to Flight 17.
Ukrainian and US officials say the Boeing 777 was shot down by a Russian-made surface-to-air missile fired by the rebels.
Russia and the rebels have denied any involvement and blame Ukraine.
The longer the site remains unguarded, the smaller the chances of recovering evidence that could clarify who shot down the plane.
Heavy fighting broke out around midday Sunday near the crash site and the nearby town of Torez, where an air-raid siren sounded continually and artillery explosions were heard to the north.
Residents scrambled to move into basements. Reporters in Torez said rebels seemed in a state of alarm as they drove cars at high speeds.
Earlier Sunday, local separatist commanders told reporters at the site that they could no longer guarantee the safety of the about 14 square miles of debris fields, as the Ukrainian military was advancing toward the area.
The road between Donetsk and Torez was closed by the separatists.
Foreign access to the crash site has been hampered by a host of problems from the start, with heavily armed rebels initially restricting the movements of foreign experts. Ukraine then asserted that its Parliament needed to endorse operations by the police from the Netherlands and elsewhere.
The Dutch police deployment Sunday, which was ordered overnight by the Ministry of Security and Justice in The Hague, reversed an earlier decision by the head of a Dutch police mission in Kharkiv to delay movement toward the crash site until a vote on Thursday by the Ukrainian Parliament in Kiev, the capital.
The Ukrainian government, which does not control the crash area but considers it an inviolable part of its territory, has been loath to see foreign governments negotiate with pro-Russia separatist leaders based in Donetsk, the capital of a self-declared republic that no foreign state, including Russia, has recognized.
Malaysia has been particularly active in reaching out to the rebel leadership. It brokered a deal last week under which the rebels handed over the downed plane’s data and voice recorders they had seized at the crash site.