Fighting rages in rebel-held city in eastern Ukraine despite rebel request for a cease-fire

Ukrainian government soldiers drive their tank with a Ukrainian national flag in Donetsk region, eastern Ukraine, Saturday, Aug. 9, 2014. A top commander of the pro-Russia insurgency in eastern Ukraine said Saturday that Ukrainian forces have seized Krasnyi Luch a key town, leaving the rebel region's largest city of Donetsk surrounded. (AP Photo/Evgeniy Maloletka) (The Associated Press)

Ukrainian government soldiers sit atop of a tank with the words reading "To Lviv" in Donetsk region, eastern Ukraine, Saturday, Aug. 9, 2014. A top commander of the pro-Russia insurgency in eastern Ukraine said Saturday that Ukrainian forces have seized Krasnyi Luch a key town, leaving the rebel region's largest city of Donetsk surrounded. Lviv is an Ukrainian town (AP Photo/Evgeniy Maloletka) (The Associated Press)

A Ukrainian boy walks past a statue of Soviet Union founder Vladimir Lenin decorated with a Ukrainian national flag in Kramatorsk, eastern Ukraine, Saturday, Aug. 9, 2014.(AP Photo/Evgeniy Maloletka) (The Associated Press)

Fighting is raging in the eastern Ukrainian city of Donetsk, one day after pro-Russian rebels there said they were ready to agree to a cease-fire in order to prevent a "humanitarian catastrophe."

One person was killed and 10 injured in shelling that started early Sunday morning and continued into the day, city council spokesman Maxim Rovinsky told the Associated Press by phone.

Associated Press reporters heard 25 loud explosions in 30 minutes in the center of Donetsk on Sunday. At least 300,000 of the city's 1 million residents have fled as violence escalates between Ukrainian government forces and pro-Russian separatists.

On Saturday, rebel leader Aleksandr Zakharchenko called for a cease-fire, in a move that could be aimed at increasing international pressure on Ukraine to allow in a Russian aid mission.