Security officials in Yemen say fighting is continuing between rebels and government soldiers in the north of the country.
The officials said Saturday that government troops and rebels clashed violently overnight in the Malahidh area in the Sa'ada and Amran provinces, near the border with Saudi Arabia, with an undetermined number of casualties.
Yemen's government said in a statement issued early Saturday the rebels had violated a cease-fire imposed late Friday.
The government had announced that it would suspend its military offensive so aid agencies could deliver food and medical supplies to civilians displaced by fighting in the northern provinces.
The rebels responded to the government's announcement by saying they would remove land mines and barriers, and end attacks on government soldiers.
The International Committee of the Red Cross and the Yemen Red Crescent Society said Thursday it had registered more than 25,000 displaced persons. The United Nations says at least 150,000 people have been displaced during five years of fighting.
Yemen said Friday its forces killed three rebel leaders in Sa'ada province.
In August, Yemeni President Ali Abdullah Saleh began an air and ground offensive against rebels from the Shi'ite Zaidi sect, also known as al-Houthis.
Zaidis dominate northwestern Yemen, but are a minority in the country. Since 2004, the rebels have been fighting against what they say is oppression by the government.
The rebels accuse Saudi Arabia, a strong ally of Yemen, of providing military support to the Yemeni government. Yemen's government has denied this.