A fire in a Yemeni prison known for its overcrowding killed eight inmates on Saturday, a security official said.

The blaze was reported in several rooms of the central prison in the city of Ibb, some 200 kilometers (120 miles) south of Sanaa, the official added, without saying whether it was thought to have been started deliberately.

A Saudi diplomat and his bodyguard were killed in broad daylight when their car was raked with gunfire by unidentified assailants in the Yemeni capital on Wednesday, a diplomatic source said.

"Gunmen dressed in the central security forces' uniforms opened fire heavily at the car of the Saudi diplomat in Sanaa, causing it to flip over, killing him and his bodyguard," the source told AFP on condition of anonymity.

U.N. leader Ban Ki-moon arrived in Yemen on Monday to mark the first anniversary of a transition deal that resulted in strongman Ali Abdullah Saleh handing over power, media and diplomats said.

On his first visit to the impoverished Arabian Peninsula country, the U.N. Secretary General will hold talks with President Abdrabuh Mansour Hadi and Gulf Cooperation Council head Abdul Latif al-Zayani who is also in Sanaa, according to official news agency SABA.

Five Yemeni army officers being held by a shadowy Islamist group in Syria are students at a military academy in Aleppo and are not involved in the fighting that has engulfed the country, a Yemeni official said.

In a statement released late Monday on the ministry of defense website, the unnamed official denied the officers had "any link at all, and they did not participate in the events in Syria."

The U.S. embassy in Yemen has suspended all consular services for two weeks, the mission said in a statement on its website, after four people were killed in violent anti-American protests in Sanaa.

The statement, published Saturday, said the embassy will be "closed for all consular services through September 29," warning citizens of the "potential" for protests near the mission.

The United States has sent Marines from the Fleet Anti-terrorism Security Team to help protect its embassy in Yemen during demonstrations, the Pentagon said Friday.

"A FAST platoon is now on the ground in Sanaa," spokesman George Little told reporters, describing the deployment of the 50-strong unit as a "precautionary step" amid anti-American unrest in the Middle East.

A firefight erupted Tuesday between Yemeni security forces and gunmen, dressed in police uniforms, who had been surrounding the headquarters of the interior ministry, witnesses said.

The gunmen, who were previously working unofficially in Yemen's police department, had been surrounding the ministry's headquarters in al-Hasaba district of Sanaa since Sunday, demanding that they be enrolled back into the impoverished country's police force.

Gunmen loyal to ousted Yemeni ruler Ali Abdullah Saleh on Sunday seized a security building near the Interior Ministry in the capital for a few hours before vacating it, a security official said.

The official said the gunmen were sent by a former security official and a relative of Saleh. After taking over the building in Sanaa, they blocked off the airport highway where it is located.

A suicide bomber blew himself up at the entrance of a police academy in the Yemeni capital Sanaa on Wednesday, killing 20 people and wounding dozens more, a security official told Agence France Presse.

A separatist from Yemen's southern movement was killed and four other people were wounded, including two women, in clashes with police in the port city of Aden on Wednesday, a local activist said.

"The police came into the Mansoura district and opened fire after residents came out to protest the police presence," Nizar al-Saeedi told Agence France Presse, adding that "one person was killed and four others were wounded."