A bomb exploded Saturday in a Tripoli street housing the Algerian, Greek and Saudi embassies, lightly damaging a car, hours after a soldier was wounded in a bombing in Libya's second city Benghazi.

A security source said the homemade bomb, locally known as "gelatina", had been placed near a car on a street in the central district of Dahra where the three embassies are located.

A Palestinian youth was killed when a tunnel linking Egypt to the Gaza Strip collapsed on Saturday, Palestinian medical sources said.

"Mussa Ghonaim, 26 years old, was killed in the tunnel collapse south of the town of Rafah," the sources said.

Yemen's air force has been the target of "sabotage", the country's military aviation chief said in a televised interview, days after a fighter jet crashed in the capital Sanaa.

"The air force is the target of systematic sabotage," General Rashed al-Janad told the private channel Al-Saida in the interview broadcast late on Friday.

Rebels in Syria have seized control of four deserted Alawite villages in the central province of Hama, the Syrian Observatory for Human Rights said on Saturday.

President Bashar Assad hails from the Alawite community, which is an offshoot of Shiite Islam, while the rebels are predominantly Sunni Muslims.

Tunisian security forces deployed in strength on Saturday after Salafist movement Ansar al-Sharia called on its hardline Islamist supporters to defy a government ban on its annual congress.

There was a heavy police presence at tollbooths along the main highway from the capital to the central city of Kairouan where the Salafists have vowed to hold Sunday's gathering, Agence France Presse correspondents reported.

Violence in Iraq killed 11 people on Saturday including a police officer, his wife and two children, while gunmen kidnapped up to 10 people, among them police, officials said.

The attacks are the latest in a wave of violence that has killed more than 270 people since the beginning of May, as tensions simmer between Iraq's Sunni minority and Shiite majority.

Suspected Al-Qaida gunmen shot dead a Yemeni intelligence officer in a drive-by attack in the southern city of Mukalla, capital of the southeastern Hadramawt province, a police source said on Saturday.

Two men riding a motorbike shot Colonel Abdullah al-Ribaki on Friday evening in a residential area of Mukalla, the source said, adding: "Al-Qaida is behind this killing."

A drive-by bomb attack on a checkpoint in the heart of Libya's restive second city of Benghazi slightly wounded a soldier early on Saturday, a security official told AFP.

"A bomb was thrown from a car at an army checkpoint at the Dubail crossroads in the center of Benghazi," the official said, speaking on condition of anonymity.

A prominent Syrian actress and activist who was detained by regime forces earlier this week was released after several hours, a human rights lawyer said on Saturday.

"The security forces released the actress May Skaf around 10:30 pm (1930 GMT) on Thursday," Anwar al-Bunni told AFP.

Demonstrators calling for Egypt's Islamist President Mohamed Morsi to resign and demanding early elections clashed with riot police in Cairo late Friday.

Hundreds of people had marched on Cairo's Tahrir Square on Friday for the protest, called by a number of opposition groups.