Even as Ukraine's new president-elect pledged to travel to eastern regions to seek peace with insurgents, Ukrainian fighter jets attacked armed insurgents who took over Donestk airport on Monday, Ukraine security officials said.
Vladislav Seleznyov, a spokesman for Kiev's anti-terrorist operation, wrote on his Facebook page that the military had given an ultimatum to the armed men to lay down their arms. He said the gunmen didn't comply and the military launched an air strike.
Several helicopters also joined the attack, which lasted at least a half hour and involved Ukrainian paratroopers, the BBC reports.
The airport was shut down earlier after insurgent showed up to demand that Ukrainian forces, which have been patrolling the airport permiter, be withdrawn, Reuters reports.
Denis Pushilin, a leader of the separatists, said they had sent their men to the airport after some of their supporters were detained.
A Reuters photographer earlier saw three trucks carrying dozens of armed men towards Sergei Prokofiev International Airport.
"The rebels are in the terminal. The rest of the airport area is controlled by the (Ukrainian) National Guard. The two sides are in talks now," airport spokesman Dmitry Kosinov told Reuters before the gunfire broke out.
It was not clear whether the attack by rebels was a demonstration of defiance or a last gasp effort following voting on Sunday that elected 48-year-old chocolate magnate Petro Poroshenko as president.
Poroshenko promised to negotiate an end to a pro-Russia insurance in the east and said he was willing to begin talks with Moscow.
Russia quickly welcomed the offer, raising hopes that his election will indeed ease the protracted crisis that has fueled tensions unseen since the end of the Cold War.
Upon claiming victory in Sunday's vote, he said his first step as president would be to visit the Donbass eastern industrial region, where pro-Russia separatists have seized government buildings, declared independence and battled government troops in weeks of fighting.
"Peace in the country and peace in the east is my main priority," Poroshenko said Monday, signaling that he would bring to an end the Ukrainian army's much-criticized campaign to drive out the armed pro-Russia separatists.
"The anti-terrorist operation cannot and should not last two or three months," he said. "It should and will last hours."
The military operation has caused civilian deaths and destroyed property — angering many eastern residents — while still failing to crush the rebellion.
A group of European election monitors said Monday that while masked gunmen intimidated votes in eastern regions and kept the turnout low that the overall voting met international standards.
Officials did not problems in the east, especially in Donetsk and Luhansk, where masked gunmen intimidated voters by smashing ballot boxes, shutting down polling centers and issuing threats.
Less than 20 per cent of polling places were open in the eastern regions, officials said. In Luhansk, voting did not take place in 10 of 12 election districts and 14 of 22 in Donestk, officials said.
But nationwide, about 60 percent of Ukraine's 35.5 million eligible voters turned out Sunday, and long lines snaked around polling stations in the pro-Western capital, Kiev.
"The electoral and security authorities of Ukraine should be commended for their efforts -- under extraordinary circumstances -- to facilitate an election that largely upheld democratic commitments," said Joao Soares, the short-term mission coordinator for the Organization for Security and Cooperation in Europe's said Monday.
One official told reporters that the fact that separatist groups tried to keep voters away from Sunday's election showed that their claims that voters supported their own referendum vote for independence was bogus.
Even before the Donetsk airport takeover, the president-elect also had harsh words for the pro-Russia gunmen, comparing them to Somalia pirates.
"Their goal is to turn Donbass into a Somalia where they would rule with the power of machine guns. l will never allow that to happen on the territory of Ukraine," Poroshenko said, adding that he hoped Russia would support his efforts to stabilize the east.
In Moscow, Foreign Minister Sergey Lavrov said Russia appreciated Poroshenko's statements about the importance of Ukraine's ties with Russia and his pledge to negotiate an end to fighting in the east. He also noted Russia's longstanding call for the Kiev government to end its military operation in eastern Ukraine.
"We are ready for dialogue with representatives of Kiev, with Petro Poroshenko," Lavrov said at a briefing, adding it was a chance that "cannot be wasted." He emphasized that Moscow saw no need for any involvement by the United States or the European Union in those talks.
"We don't need any mediators," he said pointedly.
With votes from 75 percent of the precincts counted Monday, Poroshenko was leading with about 54 percent in the field of 21 candidates. Former Prime Minister Yulia Tymoshenko was running a distant second with 13 percent. If those results hold, Poroshenko would avoid a runoff election next month with the second-place finisher.
Speaking to reporters, Poroshenko struck a tone of unity Monday, saying he had no "rivals or political opponents in the race" and all of the other main candidates have congratulated him on his win.
"More than ever, Ukraine now needs to be united," he said.
Mykhaylo Okhendovsky, chairman of the Central Election Commission, said official results would be announced by June 5.
The election, which came three months after pro-Moscow President Viktor Yanukovych was chased from office by crowds following months of street protests and allegations of corruption, was seen as a critical step toward resolving Ukraine's protracted crisis.
Since his ouster in February, Russia has annexed the Crimea Peninsula in southern Ukraine, the eastern regions of Luhansk and Donetsk have declared their independence from Kiev, and the interim Ukrainian government has launched an offensive in the east to quash an uprising.
The interim Kiev government and the West have accused Russia of backing the separatist uprising. Moscow has denied the accusations.
Unlike many other Ukrainian billionaires, Poroshenko did not make his fortune in murky post-Soviet privatizations but instead built his chocolate empire from scratch. His Willy Wonka-like chocolate stores and candies are on sale in every kiosk across the country, helping lead to the perception that he is the "good tycoon."
Many voters appreciate Poroshenko's pragmatism and his apparent knack for compromise.
President Barack Obama praised Ukrainians for participating in the voting "despite provocations and violence." Obama said the U.S. supports Ukraine's sovereignty and territorial integrity, rejects Russia's "occupation and attempted annexation of Crimea" and is eager to work with the next president.
Contributing: Associated Press