Yemen's top security body imposed an overnight curfew in restive areas of the capital, Sanaa, on Saturday after Shi'ite rebels took over the state television building amid heavy clashes and the U.N. envoy to the country signaled that a deal had been reached to end the violence.
The Supreme Security Commission said the curfew was being imposed in the north and west of the capital and will remain in place indefinitely. It follows days of clashes between Shi'ite rebels, known as Houthis, and Sunni militiamen affiliated to the Muslim Brotherhood's Islah party that have left more than 140 dead and prompted thousands to flee.
The fighting has raised fears of an all-out sectarian conflict in an impoverished country already grappling with a powerful local al-Qaida affiliate and an increasingly assertive separatist movement in the south.
Mohammed Abdel-Salam, the spokesman of Shi'ite rebels known as Houthis, said in a statement posted on his official Facebook page that his group took over the TV building after a heavy exchange of gunfire with troops guarding the building.
All three state TV networks went off the air, and witnesses said the building was on fire. Clashes were ongoing late Saturday between Houthis and army troops near an army barracks in the capital.
As the Houthis consolidated their grip over the TV building, the United Nations envoy to Yemen, Jamal Benomar, announced a deal that could end the fighting.
"An agreement has been reached following intense consultations with all the political parties ... to resolve the current crisis," said a statement posted on Benomar's Facebook page.
He said that preparations were underway to sign the deal, which he described as "a national document that will advance the path of peaceful change, and will lay the foundations for national partnership and for security and stability in the country."
No further details were available on the content of the agreement. Benomar has been holding talks with Hawthi rebels in their northern stronghold of Saada along with Yemen's President Abed Rabbo Mansour Hadi, who has kept channels open with Houthis. The United Nations has been trying to mediate a deal between Hadi and the Houthis, who say they seek economic reforms and a new government.
Just under half of Yemen's population is Shi'ite, but they mainly adhere to the Zaydi strain of Shiism, which is seen as very close to Sunni Islam. The two communities have long been intertwined in the political elite and military.
The Houthis waged a six-year rebellion until 2010 against long-ruling President Ali Abdullah Saleh. The following year the country was convulsed by an Arab Spring-inspired uprising, and Saleh was eventually forced to step down in an agreement that allowed his loyalists to maintain considerable power.
In recent months the Houthis surged from their stronghold in the north, taking a string of cities and fighting their way to the outskirts of the capital, where they have held mass demonstrations. Their critics accuse them of being a proxy of Shi'ite powerhouse Iran and of seeking to seize power in Yemen, claims the movement denies.
Fighting on Saturday took place on the road to the international airport and near a major military base, the TV building and on two university campuses, north and west of the capital. The fighting forced many families to flee their homes and trapped others.
The military base, around which fierce clashes flared, was home to a national army unit led under Saleh by former Maj. Gen. Ali Mohsen al-Ahmar, who fought against the Hawthi insurgency. After Saleh's ouster, the armed forces were restructured and al-Ahmar was appointed as military adviser to the new president.
The base was to be handed over to local authorities and transformed into a public garden, but it remains under al-Ahmar's control and the Houthis say he uses the base to recruit militias to fight them.
Shells from the fighting around the base hit the walls of Sanaa University nearby, prompting authorities to cancel classes there as well as at public and private schools.
Hawthi fighters meanwhile pressed their assault on Iman University, a bastion of Sunni hard-liners seen as a recruitment hub for militants. The school is run by cleric Abdul-Majid al-Zindani, who is considered by Washington to be a "specially designated global terrorist."