Ukrainian forces launched a full-scale military operation against pro-Russia separatists in the east on Tuesday, hours after the country's president ended a cease-fire agreement.
The Defense Ministry said Ukrainian forces "carried out strikes from the air and on land" Tuesday morning against separatist positions in eastern Ukraine.
"I can inform you that in the morning the active phase of the anti-terrorist operation was renewed," Ukraine's parliament speaker Oleksander Turchynov told MPs on Tuesday, according to the BBC. "Our armed forces are carrying out strikes on terrorist bases and checkpoints."
Fighting was reported in several areas across the region, including at posts along the Russian border that Ukrainian forces had lost to separatists in recent weeks, as well as near the international airport in Donetsk, the Wall Street Journal reported. Four civilians were killed and five were wounded in the city of Kramatorsk when a bus was hit by a shell early Tuesday, the paper reported, citing the Interfax news agency.
It wasn't clear which side fired the shots.
Military spokesman Oleksiy Dmytrashkovsky said one service member was killed and 17 wounded over the past 24 hours in rebel attacks and an Su-25 attack aircraft was damaged.
Early Tuesday, Petro Poroshenko, Ukraine's prime minister, made a televised address vowing that "we will attack, and we will free our country."
The idea behind the truce, which was announced June 20 and expired at 10 p.m. Monday, was to give pro-Russian rebels a chance to disarm and to start a broader peace process including an amnesty and new elections. Poroshenko, a wealthy candy magnate elected May 25, had already extended the cease-fire from seven days.
But rebels did not disarm, and the cease-fire was continually violated, with both sides blaming each other. Rebels called the cease-fire fake and did not yield to Poroshenko's latest push to get them to turn over key border crossings with Russia and permit international monitoring.
"The unique chance to implement the peace plan was not realized. It happened because of the criminal actions of the militants,” Poroshenko said, according to Reuters. “They publicly declared their unwillingness to support the peace plan as a whole and in particular the ceasefire."
Sergei Naryshkin, the speaker of Russia’s lower house of Parliament and an ally of Putin, called for a new cease-fire.
"We think that without a truce, without the start of dialogue, it is simply impossible to restore peace, justice and law and order in Ukraine," he said.
Russia’s Foreign Ministry also suggested that the U.S. had a role in Poroshenko not extending the ceasefire, Reuters reports.
"There is an impression that the change in Kiev's position ... could not have come about without influence from abroad, despite the position of leading EU member states," it said in a statement from Moscow.
The Associated Press contributed to this report.