There is growing concern that Islamic militants are taking advantage of the unrest in Yemen.
Yemen is the home of al-Qaeda on the Arabian Peninsula, perhaps the most active terrorist network today.
After weeks of protests, the defection of key military commanders and government officials have weakened the country's President Ali Abdullah Saleh, who refuses to step down.
"Yemen is a time bomb," Saleh said in an interview with Al Arabiya television, according to a transcript published Sunday by the state-run Saba news agency. "Everyone will side with his tribe, and we will then end up with a destructive civil war."
On Monday, militants reportedly seized control of a weapons factory, a strategic mountain, and a town in a southern province. The factory in Khanfar area close to Jaar city makes munition and Kalashnikov rifles.
Residents say the explosions could be heard up to 10 miles away and several ambulances have been bringing the injured to al-Razi hospital in Jaar on Monday.
In another province of Yemen, security officials say suspected al-Qaeda gunmen killed seven soldiers and wounded seven others in an attack on a military post. The attack took place at Ubaida area in the central Marib province, another province where the militant group is active and only under nominal government control.