A Yemeni soldier mans a security point on a main road in Sanaa Twenty-four people were killed as fighting raged overnight into Thursday in the Yemeni capital Sanaa between supporters and opponents of President Ali Abdullah Saleh and Washington ordered non-emergency staff from its embassy to leave the country.
The latest fighting brought to at least 68 the number killed since Monday, according to an AFP tally based on reports by medics, the government and tribal sources.
Overnight, the battles were centred on the Arhad district north of Yemen\'s main international airport and disrupted flights, tribal and aviation sources said although airport director Naji al-Marqab insisted services were running as normal on Thursday.
At least 12 of the dead were Republican Guards, according to tribal sources, while the official Saba news agency reported that four civilians also died.
The Yemeni president, who has been in power in Sanaa since 1978, has been resisting massive diplomatic pressure to sign up to proposals by his impoverished country\'s wealthy Gulf neighbours that would see him leave office in return for a promise of immunity from prosecution.
Heavily armed clansmen of powerful tribal leader Sheikh Sadiq al-Ahmar who rallied to the opposition in March have been fighting the Guards, other security forces and Saleh loyalists since the president again rejected the Gulf plan at the weekend.
Ahmar, one of the 10 sons of Sheikh Abdullah al-Ahmar, who was Saleh\'s main ally until his death, is capable of rallying thousands of armed supporters, tribal sources say.
Tribal loyalties run deep in Yemen, the Arab world\'s poorest country, which has an estimated 60 million firearms in private hands, roughly three for every citizen.
\"The sons of Al-Ahmar and their gang shelled houses in the Al-Hasaba neighbourhood,\" an interior ministry statement carried by Saba said.
\"One of the shells hit a home killing four people, one of them a woman, and wounding 11.
\"Two members of the security forces were also killed and four wounded,\" the statement added.

On Wednesday, tribesmen occupied the offices of the state news agency Saba and national airline Yemenia. They also tried to storm the interior ministry headquarters, witnesses and a high-ranking Yemeni official said.
Armed tribesmen from Amran, north of Sanaa, were also headed towards the capital to join the battle against Saleh\'s forces, a tribal source told AFP.
The clashes came despite an appeal by Saleh late on Tuesday for supporters of Sheikh al-Ahmar to \"cease their aggression on security forces.\"
The ancestral homeland of Al-Qaeda leader Osama bin Laden, Yemen has been seen as a key partner in the US \"war on terror\" but in recent days Washington has stepped up its pressure for Saleh to sign up to the Gulf plan for his departure.
On Wednesday President Barack Obama repeated his call for Saleh to step aside.
\"We call upon President Saleh to move immediately on his commitment to transfer power,\" Obama said at a joint press conference with British Prime Minister David Cameron in London.
Later on Wednesday Washington warned its nationals \"of the high security threat level in Yemen due to terrorist activities and civil unrest.
\"The Department of State has ordered all eligible family members of US government employees as well as certain non-emergency personnel to depart Yemen,\" it said in a travel warning.
\"The Department urges US citizens not to travel to Yemen. US citizens currently in Yemen should depart while commercial transportation is available.\"

Clansmen of the Arhab tribe of hardline cleric Abdul Majid al-Zindani, who faces US sanctions as a \"terrorism financier,\" have also been involved in the fighting with Saleh loyalists.
The clashes around the airport forced flights to be diverted to Yemen\'s main southern city Aden on Wednesday, tribal sources said.