Opposition forces over the weekend took control of two important oil towns.
Brega, the main oil export terminal in eastern Libya, fell after fighting late Saturday, and rebels were victorious in Ras Lanuf, the location of a large oil refinery.
Sirte lies on the coast about halfway between Tripoli and and Benghazi.
Taking Sirte would be a symbolic victory for the rebels who have claimed a string of victories since UN-backed airstrikes began more than one week ago.
Heavy explosions separately were reported in Tripoli where Libyan officials claim more than 100 civilians were killed by coalition bombing.
Forces loyal to Gaddafi promised to fight on.
"We will fight until the last man to safeguard brother Gaddafi`s revolution," one fighter was quoted as saying.
A050/H-AK
Editor: Jafar M Sidik
Copyright © ANTARA 2011
