As government shelling continued in a besieged city in western Libya, a United Nations call for a cease-fire went unheeded on Monday.

U.N. Secretary General Ban Ki-moon and his top humanitarian envoy Valerie Amos on Monday expressed deep concern during a visit to Budapest over the magnitude of the conflict, as well as its toll on civilians.

Shelling and sniper fire by forces loyal to Libyan leader Moammar Gadhafi killed 17 people Sunday in the western city of Misrata.

The government assault continued on Monday as a chartered ship evacuated nearly 1,000 foreign workers and wounded Libyans in an international relief effort.

U.N. and Libyan officials say they reached an an agreement Sunday to allow aid workers safe passage to Misrata for the evacuation. Misrata is the only rebel-controlled town in the west of the country and has been under siege for nearly two months.

Ban said the world body, which already is providing aid in the rebel stronghold of Benghazi, also will set up a humanitarian presence in the capital, Tripoli.