Tripoli, Libya (CNN) -- Opposition fighters continued to push west, entering territory loyal to Libyan leader Moammar Gadhafi, but were quickly beaten back, rebels told CNN, as diplomats arrived Tuesday in London to discuss the crisis.


The setback for the rebels highlights the tenuous nature of their recent gains and suggests they might face more resistance in the days to come.

As they moved into Umm el Ghindel -- near Sirte, Gadhafi's birthplace -- rebels began searching homes and found that Gadhafi's forces had armed residents in the area, they said. As they were talking to residents, asking them to join the opposition, gunfire broke out. Rebels told CNN they refused to fire back and began a hasty retreat. A stream of vehicles could be seen fleeing the area.