Looking for His glorious appearing! Titus 2:13

Residents reported sounds of heavy shelling throughout Saturday night in an area of the capital near the headquarters of the first armored division camp and close to the religious university of Iman.

The fighting, which intensified on Thursday after weeks of protests and clashes, appeared to be the biggest challenge yet to a U.N.-backed transition to democracy launched after veteran ruler Ali Abdullah Saleh was forced to step down in 2012.

U.N. special envoy Jamal Benomar, who had held talks with Houthi leader Abdulmalek al-Houthi in their home province of Saada on Wednesday and Thursday, announced late on Saturday that an agreement had been reached and was to be signed on Sunday.

Despite the accord, one Houthi rebel leader told Reuters they had intensified the shelling of the army division camp and driven soldiers out.

"We controlled a military unit east of the first armored division .... and we continued heavy shelling of the division headquarters and the nearby Iman university in all directions," Ali al-Emad told Reuters late on Saturday.

Al Jazeera television reported sounds of two explosions to the north of the capital towards dawn.

Fighting raged on throughout Saturday on the outskirts of Sanaa, and rebels said they had taken control of the headquarters of state television. Yemen's Higher Security Committee announced a curfew in four areas of the capital from 9 p.m. until 6 a.m., and schools were shut until further notice.

Still, President Abd Rabbu Mansour Hadi expressed support for the U.N.-brokered deal on Saturday and Houthis said their representatives would reach the capital traveling from Saada on Sunday to sign it.