Four people were killed and 21 injured when a passenger bus hit a landmine near a government-controlled town in eastern Ukraine, local officials said Thursday.
The bus had taken a side road in order to avoid a government checkpoint near the town of Artemivsk, some 50 kilometres (30 miles) north of the separatist stronghold of Donetsk, late Wednesday, said Ilia Kiva, a government-loyal deputy police chief in the Donetsk region.
"Today (Wednesday), at around 1900 (1700GMT)... a land mine blew up a passenger bus carrying civilians," he said.
"The explosion... killed four," he added.
Vyacheslav Abroskin, head of the Donetsk regional interior ministry, said 21 had also been injured in the explosion, including eight who needed hospital treatment.
A spokesman for the Donetsk regional administration told AFP that the death toll was four, and said that at least three of the injured were in a serious condition.
"The driver had wanted to avoid a Ukrainian checkpoint near Artemivsk by going through the field and he drove over a landmine," he added.
Elsewhere, the army said rebels had fired on their positions on eight occasions through Wednesday night, but did not report any casualties.
The area surrounding Donetsk continued to see the heaviest fighting, with rebels firing 120mm mortar shells at the village of Pisky, close to the airport which rebels took in January following fierce fighting, the army said in a statement.
Small arms fire was also used in the village of Shyrokyne, close to the strategic port of Mariupol, the largest city still under government control in the conflict zone, it added.
More than 6,000 people have died in fighting between pro-Russian rebels and government troops in eastern Ukraine since April. Despite a shaky ceasefire agreed over a month ago, daily skirmishes have continued.
Within the conflict area landmines have been strewn across rural roads and agricultural fields in an attempt to make them impassable.