The Associated Press

BETHLEHEM, West Bank Dec 20, 2005 Gunmen on Tuesday seized the rooftop of Bethlehem's city hall near Manger Square and the Church of the Nativity, and pointed their weapons at Palestinian police below, witnesses said.

The standoff came just four days before Christmas. The Church of the Nativity, one of Christianity's holiest shrines, stands over the grotto where tradition says Jesus was born.

It was not immediately clear why the gunmen were threatening the police or why they had seized the rooftop.
Why seize only the rooftop? Why not the whole building?