An army officer was killed on Sunday in the restive Libyan city of Benghazi when a bomb placed under his car exploded, a security forces spokesman told AFP.

The blast also seriously wounded the officer's wife and two children, who were with him at the time.

"Suleiman al-Fissi, a military intelligence officer, was killed today when his car exploded. His wife and two children, who were with him, were injured," Colonel Milud al-Zwai said.

Fadia al-Barghathi, spokeswoman for Benghazi's Al-Jala hospital, confirmed the officer had been killed and said his wife and children had been seriously injured in the attack.

The eastern city of Benghazi, cradle of the 2011 uprising that toppled dictator Moamer Kadhafi, has been rocked by a wave of attacks against police and army officers.

And on Saturday a bomb targeted one of the few cafes in Benghazi where women could go before it opened in the morning, damaging the building but not wounding anyone.

Authorities have tried to impose order in Benghazi, but attempts to tackle the violence by deploying police and troops have proved ineffective.

Groups of ex-rebels who fought to topple Kadhafi were charged with maintaining security after the uprising, but many have been transformed into militias and have carved out their own fiefdoms across the vast, mostly-desert country.