Separatist rebels in eastern Ukraine shot down a military helicopter Thursday, killing 12 troops including an army general, acting President Oleksandr Turchynov has said.
One soldier survived but is listed in critical condition, a statement by Ukraine\’s National Guard said.
Earlier reports put the number of dead at 14.
Acting President Oleksandr Turchynov told parliament Thursday that "terrorists" used a shoulder-launched missile to down the helicopter near the separatist-held city of Slovyansk.
Among those killed was General Serhiy Kulchytskiy of the Ukrainian Interior Ministry.
Meanwhile, a rebel leader in the eastern city of Donetsk acknowledged that some of his fighters that were killed in a government offensive earlier this week had been "volunteers" from Russia.
Also Thursday, an insurgent leader in eastern Ukraine said his fighters are holding four observers from the Organization for Security and Cooperation in Europe and promised that they would be released imminently.
Vyacheslav Ponomarev, the self-proclaimed "people\’s mayor" of Slovyansk, a city in the Donetsk region, told The Associated Press the monitors — who are from Turkey, Switzerland, Estonia and Denmark — were safe.
"I addressed the OSCE mission to warn them that their people should not over the coming week travel in areas under our control. And they decided to show up anyway," Ponomarev said.
"We will deal with this and then release them," he said, without setting any specific timeframe.
The OSCE said it had lost contact with one of its four-man monitoring teams in Donetsk on Monday evening. Rebels have previously kidnapped military observers working under the auspices of the OSCE.
The OSCE monitors have been deployed to Ukraine to monitor security situation following Russia\’s annexation of Crimea and a pro-Russia separatist insurgency that has engulfed regions in eastern Ukraine. They also observed Sunday\’s presidential vote, won by billionaire candy magnate Petro Poroshenko.
Poroshenko has promised to negotiate with people in the east, where insurgents have seized government buildings and fought government troops for a month-and-half. But he also vowed to continue a military operation to uproot the armed rebels and bring it to a quick end.
In the most ferocious battle yet, rebels in Donetsk tried to take control of its airport Monday but were repelled by Ukrainian forces using combat jets and helicopter gunships. Dozens of men were killed and some morgues were overflowing Tuesday. Some insurgent leaders said up to 100 fighters may have been killed.
Chechnya\’s leader says the country hasn\’t sent fighters to join rebels in eastern Ukraine, denying a charge that gained substance after Chechens were reportedly found in the aftermath of recent fighting in Donetsk.
Ramzan Kadyrov issued a statement on Instagram Tuesday "officially" denying claims that, as he put it, "Chechen units" from Russia had "invaded" eastern Ukraine.
"No \’Chechen servicemen\’, especially \’Chechen military convoys\’, are taking part in the conflict," Kadyrov wrote.
He said Chechnya was a region of the Russian Federation which, under Russia\’s constitution,"has no armed forces," adding that if a Chechen was seen in the conflict zone in eastern Ukraine, "then it is his personal business."
Britain\’s Financial Times reported Tuesday it found a group of armed men in Donetsk who said they were part of a Chechen unit that had travelled to Ukraine to fight with the separatists.
The newspaper quoted one of the men as saying that Kadyrov had given the order for them to join the fight.