DONETSK, Ukraine -- After several days of setbacks, Ukrainian security forces sought to take the offensive Tuesday from pro-Russian 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, however, 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 heart of the city -- a move that could lead to high casualties on both sides and among civilians. Residents were urged Tuesday to remain inside their homes while battles raged on the outskirts of Slovyansk.
At least 181 people, including 59 Ukrainian soldiers, have died in clashes in the east since fighting began in April, Ukraine's top prosecutor, Oleh Makhnitsky, said. Ukrainian officials say they do not keep track of insurgent deaths, so the actual total is likely to be much higher.
Many in the southeast fear the number could rise dramatically if the military launches a campaign to retake the many towns and cities across the region that have been commandeered by insurgents. Slovyansk is widely considered one of the rebels' best-fortified positions, and the insurgent leaders in the city have aggressively deployed their forces to take down government aircraft and ambush troop convoys.
Stella Khorosheva, a spokeswoman for the rebels in Slovyansk, called Tuesday's assault "the heaviest and longest attack" since the government's counterinsurgency operation began several weeks ago.
Khorosheva said the city came under bombardment from artillery and helicopter gunships at 6 a.m., with only brief pauses throughout the day.