Gunmen tried to assassinate the head of the Libyan army Saturday in a bold daylight attack in the country’s capital, setting off hours of intense gunbattles along the main highway to the airport. Assailants in Tripoli also attacked one of Libya’s largest military bases.

The gunmen were believed to be from renegade groups of former rebel fighters. The violence deepens concerns about unity among the ex-rebels — many of whom remain heavily armed — while the police and military struggle to restructure their forces after the overthrow of Moammar Gadhafi.

Military officials said revolutionary fighters from the western mountain town of Zintan were likely behind the violence. They spoke on condition of anonymity because an investigation was still under way.