NEW : Government says commanders who fire on civilian buildings will face charges . The military has been accused of using excessive force in the past, but this is a new level of brutality and it's not clear how many people have died as a result. Libyan government says it may request international troops to help stop the violence . In a statement aired on a private Libyan television channel , one of the three main Zintan groups in Tripoli said that at least two members of the force defending positions at the airport were killed in a rocket attack . U.N. removes its staff in Tripoli for first time since revolution .
NEW : Government says commanders who fire on civilian buildings will face charges . The military has been accused of using excessive force in the past, but this is a new level of brutality and it's not clear how many people have died as a result. Libyan government says it may request international troops to help stop the violence . U.N. removes its staff in Tripoli for first time since revolution .