Flights in and out of the international airport in Donetsk in eastern Ukraine have been halted indefinitely, an announcement on the airport’s website said, according to RIA Novosti.

“The Donetsk Airport is temporarily putting on hold all flight services starting 7:00 am [4:00 am GMT]. The restart of services will be announced in a separate message,” the airport management said.

On Sunday, Petro Poroshenko, a billionaire chocolate manufacturer, claimed victory in the Ukrainian presidency. The 48-year-old won 55-percent in exit polls on a first round ballot.

"My first decisive step will be aimed at ending the war, ending chaos, and bringing peace to a united and free Ukraine," Poroshenko said at a press conference in Kiev.

"I am certain that our decisive actions will bring fairly quick results."

He also promised a dialogue with people in eastern Ukraine if he is elected.

"For those people who don't take (up) weapons, we are always ready for negotiations to guarantee them security, to guarantee their rights, including speaking the language they want," he said.