DONETSK, Ukraine —
After several days of setbacks, Ukrainian security forces sought to take the offensive Tuesday from pro-Russia insurgents in the country's southeast, launching a major assault on a rebel stronghold.
The attack on separatist positions in the city of Slovyansk began at dawn and continued throughout the day, with officials and residents reporting fierce clashes.
Much of the fighting was still conducted from a distance, with Ukrainian forces pounding rebel positions with artillery fire, residents said. Although troops were massing around Slovyansk, it was unclear whether they would attempt to enter the city.
At least 181 people, including 59 Ukrainian soldiers, have died in clashes in the east since fighting began in April, according to Ukraine's top prosecutor. Ukrainian officials say they do not keep track of insurgent deaths, so the actual total is likely to be far higher.
Many in the southeast fear that the number could rise dramatically if the military launches a campaign to retake the many towns and cities that have been commandeered by insurgents.