Heavy fighting between the Yemeni government and Al-Houthi clan rebels has left 39 people dead, security officials and witnesses say.
Reportedly, army used artillery and rockets for the third consecutive day on Monday to bombard rebel strongholds in the mountains along the border with Saudi Arabia.
According to medical officials, 26 rebels and 13 soldiers were killed in the fighting on Saturday and Sunday.
Meanwhile, a state security court on Monday sentenced four rebels to death for the killing of two army officers last year.
The four men ambushed a military vehicle on a road in the restive province of Saada last year, killing two officers and injuring two.
Saleh Habra, a senior rebel official, said Qatari representatives are scheduled to arrive in Yemen on Monday to continue mediation efforts that produced a cease-fire last year but failed to quell the violence.
Fighting between rebels loyal to the outlawed Believing Youth group, known as Houthis, and government forces has been raging on and off in the north-western province of Saada since mid-2004.
Houthis belong mostly to the Zaidi sect of Islam.