SLOVYANSK, Ukraine: Rebels in eastern Ukraine shot down a military helicopter Thursday amid heavy fighting around Slovyansk, killing as many as 14 soldiers including a general, officials said.

Acting President Oleksandr Turchynov told the Parliament in Kiev that rebels used a portable air defense missile to bring down the helicopter. He said 14 died, including Gen. Serhiy Kulchytskiy, according to the Interfax news agency.

Slovyansk, a city of 120,000 residents 160 kilometers from the Russian border, has become the epicenter of fighting between pro-Russia insurgents and government forces in recent weeks. It’s in the Donetsk region, one of the two provinces in eastern Ukraine that have declared independence from the central government in Kiev.

Meanwhile, the European Union said that Officials from Russia, Ukraine and the EU are to hold new gas talks in Berlin on Friday, under a Russian threat to cut supplies which feed several countries.

The announcement from the EU comes just days before a deadline set by Russia to cut the flow of gas if Ukraine does not pay unpaid bills.

But Ukraine, already under pressure on its frontiers from Russia, is on its knees financially.

The Kiev government condemns the insurgency that is roiling the east as the work of “terrorists” bent on destroying the country and accuses Russia of fomenting it. Russia denies the accusations, saying it has no influence over rebels, who insist they are only protecting the interests of Russian-speakers in the east.

Billionaire candy magnate Petro Poroshenko, who just won Ukraine’s presidential vote, has promised to negotiate with people in the east but has also vowed to uproot the armed rebels. He is not yet in charge however — a date is still being set for his swearing-in early next month — and has not spoken about the insurgency since his victory speech Monday.

Russia’s Foreign Ministry on Thursday denounced the use of aircraft and artillery against the rebels and demanded that Kiev end a “fratricidal war and launch a real political dialogue with all political forces and representatives of the regions.”

The separatists in Ukraine have pleaded to join Russia, but President Vladimir Putin has ignored their appeal in an apparent bid to de-escalate tensions with the West and avoid a new round of Western sanctions.

Putin has denied sending any troops into Ukraine, but fighters from Russia, including from the battle-hardened region of Chechnya, have been appearing among the separatists.

An insurgent in Donetsk, who identified himself only by his nom de guerre, Baran (Ram), told reporters Thursday that 33 Russian citizens were among the rebels killed earlier this week.

Dozens of rebels were killed — insurgent leaders said the death toll might be up to 100 fighters — when Ukrainian forces used combat jets and helicopter gunships Monday to dislodge those trying to seize control of Donetsk airport, Ukraine’s second-largest.

An insurgent leader, meanwhile, confirmed that his fighters were holding four missing observers from the Organization for Security and Cooperation in Europe and promised they would be released shortly. Vyacheslav Ponomarev, the self-proclaimed “people’s mayor” of Slovyansk, told the AP that 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 did not give a specific timeframe.

The OSCE had lost contact with the team in Donetsk on Monday evening. Their teams are in Ukraine to monitor security situation following Russia’s annexation of Crimea in March and the rise of the pro-Russia separatist insurgency.