KIEV, Ukraine -- President-elect Petro Poroshenko set Ukraine on a collision course with Russia even before the last vote had been counted, vowing to step up operations to rein in separatists in the east of the country.
"There will be a sharp increase in the efficiency of anti-terrorist operations," Mr. Poroshenko said in Kiev Monday. "They won't last two or three months; they'll last a few hours."
In Moscow, Foreign Minister Sergei Lavrov said that any escalation would be a "colossal mistake."
The difficulty of Mr. Poroshenko's task was clear in Donetsk, where paratroopers, helicopters and warplanes were deployed after rebels ignored an ultimatum to leave the local airport. A clash between government forces and gunmen near the city's railway station left one dead, the Novosti Donbassa news agency reported.
Mr. Poroshenko, a candy tycoon, is faced with a shrinking economy and a pro-Russian separatist movement that's captured large swathes of the Donetsk and Luhansk regions, threatening to rip the former Soviet republic apart. Russia annexed the Black Sea Crimean peninsula in March.
Secretary of State John Kerry said in a statement that the U.S. "respects Ukraine's sovereignty and territorial integrity, condemns and rejects Russia's occupation and attempted annexation of Crimea, and remains committed to working with Ukraine and other partners to find a peaceful resolution to the conflict."
Yet in Donetsk, the election brought no lull in the violence. As evening fell, fighter aircraft were again seen in the skies and explosions were heard in the city, with renewed fighting near the railway station, the Ostrov news website reported. Novosti Donbassa reported that a column of about 40 trucks carrying armed men was seen in Russia approaching the border with the Donetsk region. Fighting was also reported in Slovyansk and Mariupol.
In his first comments after the vote, Mr. Poroshenko said Sunday he would seek to end the "war, chaos and disorder" by visiting the troubled eastern regions and working with Russia. Ukraine's Central Election Commission declared him the winner with 54.4 percent of the vote, after 94 percent of ballots had been counted, Novosti Donbassa said.
European leaders, while calling the presidential election a success, are still facing a deeper dilemma: how to free their countries from an addiction to Russian energy. Mr. Poroshenko's victory has relieved the immediate pressure on the U.S. and the European Union to impose tougher sanctions against Russia.
The European and American reluctance to escalate in the wake of an election that was at least a partial success, a U.S. official said Monday, suggests that by finally tempering his actions and rhetoric, Russian President Vladimir Putin may have achieved much of what he sought in Ukraine.
Russia's ever-changing mix of covert action, economic threats and the annexation of Crimea, followed by soothing words, the official said, has exposed the divergence of U.S. and European Union views on Russia and the EU members' conflicting interests there, especially on energy.
"The energy crisis is a test of what the EU really is," Poland's Prime Minister Donald Tusk said Wednesday, calling it "a duel" over what's more important: "bilateral relations with Russia or relations within the EU." The only way to be "an equal partner to big suppliers" is to form a united front.
Mr. Lavrov said the fact the vote was held is positive and reiterated Mr. Putin's earlier pledge to respect the election's outcome.
NAK Naftogaz Ukrainy is prepared to pay $2 billion to OAO Gazprom by Thursday to cover arrears, said EU Energy Commissioner Guenther Oettinger. A $500 million payment would follow by June 7 if the countries' governments approve.
Energy Minister Yuri Prodan said the Ukrainian government would respond by Wednesday evening. Ukraine depends on Russia for about half its gas, and Europe gets about 15 percent of its supplies of the fuel through Soviet-era pipelines that cross Ukraine.