DONETSK, Ukraine (AP) -- Discouraged but defiant, pro-Russia separatists vowed to keep fighting the government in Kiev from the largest city in eastern Ukraine, where they regrouped Sunday after being driven out of a key stronghold.
At a rally in a central Donetsk square, the rebels were cheered on by thousands of supporters waving flags from Russia and the self-proclaimed independent Donetsk People's Republic. Many urged Russian President Vladimir Putin to quickly come to their aid -- but there was no comment Sunday from Russia.
While the rebel withdrawal Saturday from Slovyansk, a city of 100,000 they had held for months, was not a total victory, President Petro Poroshenko said purging the city of the insurgents had "incredible symbolic importance." It was unclear whether the government -- after abandoning a cease-fire last week and going back on the offensive -- was now winning the fight that had sputtered for months.
Rebel fighters from Slovyansk could be seen walking through Donetsk on Sunday in groups of 10 to 15. Most were still wearing camouflage, but some sported identical new bright-colored shorts and shirts. It was an unsuccessful effort to blend in with the civilian population, since they still carried automatic weapons.
At one money-exchange office in the city center, about 20 rebels lined up to trade U.S. dollars for Ukrainian hryvnas. The dollar is considered a more stable currency in Ukraine and Russia, but it was not known who had given them to the rebels. They refused to speak with Associated Press journalists and their mood appeared black.
Igor Girkin, defense minister of what the separatists call the Donetsk People's Republic, told the Russian television channel Life News on Sunday that he would now coordinate the fight from Donetsk.
"We will continue the combat operations and will try not to make the same mistakes that we made in the past," said Girkin, a Russian also known by his nom de guerre, Igor Strelkov. Ukrainian authorities have identified him as a veteran of the Russian military intelligence agency.
Rhetoric soared Sunday afternoon at the rally.
"We will begin a real partisan war around the whole perimeter of Donetsk," Pavel Gubarev, the self-described governor of the Donetsk People's Republic, told the crowd. "We will drown these wretches in blood."
But he said the insurgents could easily die in Donetsk if Russia did not do more to help them. Gubarev said rebels were forced to flee Slovyansk because several commanders had betrayed Girkin and left his forces there vulnerable to attack.
Despite the bravado in the city, the mood was dire Sunday at a rebel checkpoint on the outskirts of Donetsk.
"We will fight to the end because we have nowhere left to retreat," said a 32-year-old former coal miner who would give only his first name, Artyom, due to fears of retaliation. "I don't want to fall into the hands of the Ukrainian authorities."
Agreeing to speak on camera only after putting on a black face mask, he said the insurgents still hoped for help from Russia "but the hope grows weaker with every day."
Concentrating their forces in Donetsk will both help and hinder the rebels, security experts said.
"Donetsk will be a tougher nut to crack" for government forces for several reasons, said Mark Galeotti, a security expert at New York University's Center for Global Affairs.
With a population of almost 1 million, Donetsk is larger and has a greater concentration of rebel defenders. On top of that, Ukrainian forces may try to avoid using aircraft and artillery, their chief military advantages, in the city because of the damage and civilian casualties they can cause.
If government forces try to take Donetsk by street-to-street fighting "that is playing to the insurgent's strengths ... When it comes to close-quarters combat, on the whole, the insurgents have proved more effective than most of Kiev's forces," Galeotti said.
Moving the fight to Donetsk also puts more pressure on Putin to step up his support for the rebels.
Ukraine and the West have accused Russia of fomenting the insurgency by sending troops and weapons, including tanks and rocket launchers, something Moscow denies. Putin has so far resisted demands at home and by the rebels to come to their aid, wary of having more Western sanctions slapped on Russia.
"Putin now has to put up or shut up," said Galeotti. "Slovyansk could be lost. If Donetsk falls, the insurgency falls."
Much also depends on whether Poroshenko presses the attack or eases off in hopes of a negotiated solution to the unrest. He began his presidency on June 7 by outlining a peace plan and then declaring a cease-fire, but he is under public pressure to defeat the rebels.