By PETER LEONARD
Associated Press DONETSK, Ukraine (AP) - The scruffy rebels who normally populate the headquarters of the rebel Donetsk People's Republic were mostly out of view on Friday. In their place were members of a new faction, who showed up a day before with an armored personnel carrier and flushed out the occupants.
The separatists' so-called prime minister said nothing has changed - but something has clearly shifted in Ukraine's troubled east.
The balance of power in the east has teetered wildly this week. After Ukrainians elected Petro Poroshenko as the country's president and Russia said it would respect the vote, hopes rose that a resolution was in the works for the conflict between the central government and the insurgents who want Donetsk to be a part of Russia.
But a day later, the rebels launched an exceptionally bold assault, seizing Donetsk's airport. Ukraine's military responded with previously unseen ferocity, launching airstrikes and sending in paratroopers to retake the airport.
To some, the rebel operation looked like a desperate last stand. But on Thursday, rebels shot down a Ukrainian military helicopter, killing 12, including a general. And the same day, the murky Vostok Battalion established themselves in rebel headquarters in the 11-story Donetsk regional administration building, demanding it be evacuated because of what they said was the presence of looters.
The Vostok Battalion's wrath was ostensibly about the ransacking of a supermarket during the battle for the airport, but some interpreted their move as a power grab.
The battalion is believed to consist largely of Russians, bolstering fears among many Ukrainians that Russia is either directing the unrest in the east or supporting it in order to destabilize the country and seize eastern regions bordering Russia.
Donetsk insurgency leaders were at pains to stress that the takeover of their building did not signify a change of guard.
"No coup has taken place. The whole terrible panic that was whipped up over this, what you might call a police operation, is a panic that has been instigated by our so-called friends in Kiev,"said Alexander Borodai, who calls himself the prime minister of the Donetsk People's Republic.
The heavy contingent of Vostok Battalion militiamen had disappeared by Friday morning, as had the armored personnel carrier and vintage anti-aircraft gun they arrived with the day before. Inside, however, many members of the militia group were spotted in civilian clothing.
Meanwhile, there were mixed signals Friday on whether Moscow and Kiev were moving toward improving relations, a key element in resolving the conflict whatever Russia's actual role is in the east.
At talks in Berlin, Ukraine said it ordered a $786 million payment to Russia in a first step toward paying off its gas debts, and another round of talks aimed at resolving the two countries' gas price dispute was set for Monday.
Russia has stepped up pressure on Ukraine over gas lately, demanding payment up front for deliveries starting in June. It has threatened to restrict supplies starting Tuesday if no payment is made.
Moscow has put Kiev's gas debts dating back to November at $3.5 billion, and the CEO of Russian gas company Gazprom said this week that gas delivered in May could bring them to $5.2 billion. Ukraine, which saw gas price discounts granted by Russia canceled following the February ouster of pro-Russian President Viktor Yanukovych, has sought an agreement on prices before paying up.
While Russian and Ukrainian officials struggled toward a resolution of that knotty problem, Moscow fired a new legal salvo at Kiev. A spokesman for Russia's top investigative body, Sergei Markin, said a criminal case had been opened on whether to charge Ukrainian authorities and servicemen with war crimes for the offensive against rebels in the east. Russia has repeatedly denounced the offensive as a war against Ukraine's own people and demanded that forces be withdrawn from the east.
Also Friday, the Organization for Security and Cooperation in Europe said it lost contact with a five-member observer team in east Ukraine, where four members of another OSCE mission are still being held by pro-Russian rebels.
The OSCE said in a statement that it lost contact with the team, made up of four international workers and one Ukrainian translator, in the Luhansk region late on Thursday. The OSCE has been out of contact with another four-member team in the neighboring region of Donetsk since Monday.
An insurgent leader in the Donetsk region confirmed Thursday that members of the first group were in their custody. The rebels told journalists that they would "deal with this and then release them," but didn't elaborate or give a specific timeframe. The OSCE's teams are in Ukraine to monitor the security situation following Russia's annexation of Crimea and the rise of the pro-Russia separatist insurgency in the east.
Laura Mills in Kiev, Jim Heintz in Moscow and Geir Moulson in Berlin contributed to this report.