UPDATE 4-Rockets bombard Misrata, rebels say eight killed
* NATO leaders say Gaddafi trying to strangle Misrata
* Rights group says government forces use cluster munitions
* Aid ships evacuate migrants, wounded
(Adds report on cluster munitions, number of dead, quotes)
By Fredrik Dahl and Joseph Nasr
TUNIS/BERLIN, April 15 (Reuters) - Muammar Gaddafi's forces fired salvos of rockets on Friday in a second day of intense bombardment of Libyan insurgents' besieged western stronghold of Misrata, and rebels said fighting had reached the city centre.
A rebel spokesman said eight people were killed and nine wounded in the bombardment. A U.S.-based human rights group accused government forces of using cluster munitions in Misrata.
The rebel spokesman, Abdelsalam, said pro-Gaddafi forces shelled both the centre and a road leading to the port, a lifeline for Misrata's trapped civilians and the main entry point for international aid agencies.
"Today was very tough ... Gaddafi's forces entered Tripoli Street and Nakl al Theqeel road," he said by phone, referring to a main Misrata thoroughfare, the scene of heavy clashes in recent weeks, and the road to the port. Continued...