By Maria Tsvetkova
SLAVIANSK, Ukraine (Reuters) - Four Ukrainian paramilitary police were killed in fighting on Monday with pro-Russian separatists near the rebel stronghold of Slaviansk, the Interior Ministry said, in renewed violence Kiev is struggling to stop across the east.
The sound of an air siren could be heard in the center of Slaviansk and a church bell rang in the main square. Gunfire seemed to be coming closer to the center of the town.
Rebel fighters ambushed Ukrainian forces early on Monday, triggering heavy fighting on the outskirts of the city of 118,000, Interior Minister Arsen Avakov said.
A Reuters correspondent said rebels with at least two separatist armored personnel carriers fled the area, where almost continuous gunfire had been heard since morning.
"In the morning, a squad in the anti-terrorist operation was hit by an ambush by terrorist groups. They are using heavy weapons," Avakov said in a statement from near Slaviansk.
Kiev authorities describe pro-Russian separatists, who have seized control of a string of towns across the east of the country, as "terrorists". The rebels for their part say they are defending Russian-speaking areas of the east against Ukrainian "fascists" trying to root out Russian influence in the country.
Cars ferried the wounded from the sites of the clashes.
There were fatalities on the side of the separatists though no figures were available.
One civilian woman was hit in the head by a bullet, her sister told Reuters at the hospital. Her husband sat next to his sister and wept.
The uprisings began when President Viktor Yanukovich, a supporter of closer ties with Moscow, was toppled by demonstrations led by pro-Western figures in February.
(Reporting by Maria Tsvetkova, Writing by Elizabeth Piper and Ralph Boulton)