TRIPOLI, Libya (AP) — A Libyan military spokesman says ex-rebels have tried for a second time to assassinate the country’s new national army commander.

Sgt. Abdel-Razik el-Shibahy said Sunday that revolutionary fighters from the western mountain town of Zintan opened fire Saturday evening on Gen. Khalifa Hifter’s convoy in Tripoli, after failing to assassinate him hours before. He says one guard was killed and four injured in this second attack. No one was killed in the first attempt.

The Libyan military says that the conflict began when a unit from the national army tried on Saturday to take control of the capital’s airport from the Zintan fighters.

Libya’s nascent army is struggling to impose its authority over the militias that overthrow Moammar Gadhafi.