The foreign ministers of Russia and Ukraine met briefly on the sidelines of a Council of Europe conference in Vienna, Austria's foreign ministry said on Tuesday, to discuss ways to defuse the situation in Ukraine.
"There was a short greeting. They spoke briefly, but not by themselves," a ministry spokesman said of the meeting between Russian Foreign Minister Sergei Lavrov and Ukrainian Acting Foreign Minister Andriy Deshchytsia.
The meeting came late on Monday, after Ukrainian troops had fought pitched gun battles with pro-Russian militias occupying Slovyansk, and the government sent an elite national guard unit to the southern port city of Odessa as Kyiv scrambled to bring much of the country back under the capital’s control.
The Ukrainian Interior Ministry said four officers have been killed and another 30 soldiers injured in the fighting. Gunfire and multiple explosions were heard in and around Slovyansk, a city of 125,000 people that has become the focus of the armed insurgency against the new interim government in Kyiv.
Near Slovyansk on Monday, a Ukrainian military helicopter was shot down, but the pilots survived, Ukraine's Defense Ministry said.
The helicopter, an Mi-24, which came under fire from a heavy machine gun, crashed into a river. The ministry said in a statement its crew members were evacuated to a nearby camp but did not give any details of their conditions. At least three other helicopters have been shot down by pro-Russian armed groups since uprisings began in eastern parts of Ukraine early this year.
Interior Minister Arsen Avakov said on his agency's website that pro-Russian forces were deploying large-caliber weapons and mortars in the eastern region and that there were wounded on both sides.
Government troops were facing about 800 insurgents, he said.
A pro-Russian militia spokesman in Slovyansk said an unspecified number of people had been killed and wounded in the clashes, including a 20-year-old woman killed by a stray bullet.
Both sides indicated that fighting was taking place at several sites around the city.
The tensions in Ukraine also raised concerns in neighboring Moldova, another former Soviet republic, where the government said late Monday it had put its borders on alert.
Moldova's breakaway Trans-Dniester region, located just northwest of Odessa and home to 1,500 Russian troops, is supported by Moscow, and many of its residents sympathize with the pro-Russia insurgency.
Ukraine's Avakov also said on Monday he sent a new special forces unit into the southern port city of Odessa after the "outrageous" failure of police to tackle pro-Russian separatists in a weekend of violence that killed dozens.
Odessa, a southwestern port with a broad ethnic mix, including Russians, Ukrainians, Georgians and Tatars, is seen in Kyiv as something of a bellwether, a warning of danger if rebellion spreads beyond the Russian-speaking east.
Avakov said the new Odessa force was based on "civil activists" who wanted to help the Black Sea city "in these difficult days.” The entire leadership of the local police had been sacked and could face criminal action.
The Odessa violence was the deadliest since Moscow-oriented President Viktor Yanukovych fled to Russia in February and pro-Russian militants launched uprisings in the industrial east.
"The police in Odessa acted outrageously, possibly in a criminal fashion," Avakov said on his Facebook page. "The 'honor of the uniform' will offer no cover."
Ukrainian leaders have made it clear they see the police force across wide areas of the country as unreliable in the face of rebellion, which they say is backed by Moscow and led on the ground by Russian special forces. The units Avakov referred to emerged partly from the uprising against Yanukovych.
Odessa, a city of a million people, has two ports, including an oil terminal, and is a key transport hub.
Kyiv’s anger on Monday focused on the Odessa police decision to release 67 largely pro-Russian militants after supporters besieged and stormed a police station on Sunday.
For weeks, Odessa had remained largely peaceful even as violence erupted across eastern Ukraine. But 46 people died Friday after riots broke out there between pro-Russia and pro-Ukraine groups and a government building was set on fire.
While Russian President Vladimir Putin has made no public comment on the situation in Ukraine since the Odessa fire, which killed more than 30 Russia supporters, several Russian politicians have ramped up their anti-Ukraine rhetoric, and Russian state media outlets have referred to the fire as genocide.
Al Jazeera and wire services