Bombings in the center of the ethnically-mixed city of Baquba, north of Baghdad, killed six people including four children on Tuesday, an army officer and a doctor said.

The attacks struck the homes of a Sunni anti-Qaida militiaman and a formerly internally-displaced Shiite family, both of which are in a neighborhood that was an insurgent stronghold during the worst of Iraq's sectarian bloodshed.

Bahraini activist Abdulhadi al-Khawaja described his imprisonment as a "crime" on Tuesday as he attended his trial for the first time since launching a hunger strike in February, arriving in a wheelchair.

"The continuation of my arrest is a crime," Khawaja, wearing a white shirt and black trousers, told the appeals court. "Stop this sham trial."

A dust storm shut Iraq's airport on Tuesday, an Iraqi Airways official said, a day ahead of key talks between world powers and Iran on the Islamic republic's controversial nuclear program.

"There are no take-offs or landings ... because of bad weather," the official told Agence France Presse on condition of anonymity.

A bomb rocked the Damascus neighborhood of Qaboon during the night killing five people, the Syrian Observatory for Human Rights said on Tuesday.

The Britain-based group gave no further information on the deadly explosion but said powerful blasts were also heard overnight in several regions across the country, including central Hama and the coastal cities of Banias and Latakia.

A prominent Palestinian writer who was jailed in Syria for nearly three weeks described the facilities as "human slaughterhouses," saying security agents beat detainees with batons, crammed them into stinking cells and tied them to beds at night.

Salameh Kaileh, 56, was arrested April 24 on suspicion of printing leaflets calling for the ouster of Syrian President Bashar Assad, who is fighting a 15-month-old uprising against his rule. Kaileh's story offers a rare inside glimpse into the conditions faced by detainees held by the country's feared security services.

A senior U.N. official urged authorities in the central Syrian city of Homs Monday to release political prisoners and allow peaceful demonstrations.

Homs has been hard hit in violent clashes between anti-government protests and pro-government security forces. Last week, at least 15 civilians were "summarily executed" there by regime forces, according to the Syrian Observatory for Human Rights.

Yemen's longtime strongman, who resigned in February in the face of a bloody year-long uprising against his rule, has undergone "routine" tests and "minor operations," his party announced on Monday.

Saleh "was admitted to a hospital run by the Republican Guard (elite troops under the command of his son Ahmed) for routine tests on Sunday, and has left the facility," General People's Congress deputy secretary general Sultan al-Barakani told Agence France Presse.

Al-Qaida militants on Monday claimed they raked with gunfire a convoy carrying four U.S. military advisers in Hudaida, but American officials said they had no such personnel in the west Yemen port city.

Al-Qaida said in a statement that jihadists had opened fire on Sunday on two cars carrying four American military advisers who were in the Red Sea city on a training mission with the Yemeni Coast Guard.

Palestinian security forces arrested 10 members of the Islamic Jihad in the Jenin refugee camp on Monday, a local leader of the radical movement said.

Ghassan Sa'adi, head of the Islamic Jihad in the Jenin refugee camp, located in the occupied West Bank, told Agence France Presse he did not know why they had been detained.

Campaigning for Egypt's landmark presidential election ended on Monday, wrapping up an unprecedented exercise in democracy made possible by the 2011 popular uprising that ousted President Hosni Mubarak.

According to the electoral rules laid down by the Supreme Presidential Election Commission, the dozen candidates cannot give any media interviews or make public appearances until polls close on Thursday after the two-day election.