- Top stories: Turmoil in the Middle East
Meanwhile, the highest-ranking U.S. diplomat in the Middle
A rebel spokesman said forces loyal to Gadhafi also shelled the rebel-held town of Zintan and massed troops close to another town in the mountainous region bordering Tunisia, intensifying operations on the war's western front.
Confirming the proposed use of helicopter gunships, French Foreign Minister Alain Juppe told reporters in Brussels the move was in line with a United Nations resolution to protect Libyan civilians and NATO's military operations.
'More accurate hits'
"What we want is to better tailor our ability to strike on the ground with ways that allow more accurate hits," he said. "That is the goal in deploying helicopters."
Saleh has refused to ink an accord brokered by the Gulf Cooperation Council (GCC) that would have seen him cede power within 30 days in exchange for immunity from prosecution for himself and his aides. Several people were wounded as tribesmen and police traded fire with machine guns and grenades near the home of tribal chief Sadiq al-Ahmar, a security official and witnesses said, without giving a breakdown.
Sources close to Ahmar said the fighting erupted after security forces tried to deploy around the tribal leader's residence and that loyalist gunmen had retaliated. But the security official said police intervened after Ahmar's gunmen assaulted a school. And the interior ministry said the tribal gunmen fired on the official Saba news agency and other buildings, while the journalists' union said a number of its members were trapped inside by the clashes. The reports could not be independently verified as the area was cordoned off.
Ahmar, who heads the Hashid tribal federation, the largest in deeply tribal Yemen and a former crucial source of Saleh's power, in March pledged his support for the opposition. Yemen's opposition vowed earlier on Monday to step up street protests, while insisting on efforts to avoid violence. "Our only option is to intensify the peaceful revolt and continue to choke the regime, then finish it," said Mohammed al-Qahtan, a spokesman for the Common Forum coalition of parliamentary opposition parties."The regime is trying to push the situation toward violence, but it will not push the country into war," he said.
Saleh on Sunday explicitly warned of civil war as he refused to sign the transition plan brokered by impoverished Yemen's oil-rich Arab neighbours in the Gulf. "If they remain stubborn, we will confront them everywhere with all possible means," Saleh said. "If they don't bow, and want to take the country into a civil war, let them be responsible for it and for the blood that was shed and that will be shed if they insist on their stupidity."