Protesters enter Sanaa's "Change Square" before Friday prayers

Ahead of Friday prayers, an Al Jazeera correspondent tours the perimeter of what protesters have dubbed "Change Square" in Yemen's capital.

Civilians have set up checkpoints next to defensive rock piles to prevent weapons from entering the square, but professional army soldiers have joined their ranks as well.

Opposition groups have dismissed President Ali Abdullah Saleh's offer to step down by year's end - after 33 years in power - after dozens of protesters were killed one week ago in Change Square.