Tony Birtley reports from the Sirte front line in Libya

National Transitional Council (NTC) forces say they have cornered loyalists of Muammar Gaddafi in a small area in the centre of Sirte, the hometown of the deposed Libyan leader that has become the key battleground in their final push to control the country.

Al Jazeera's Tony Birtley, reporting metres away from the frontline on Tuesday afternoon, said that the "noose was tightening" around Gaddafi's remaining fighters, but that they were waging a fierce rearguard effort, and had "a lot of ammunition and a lot of resolve"