The Yemini army has entered into its fifth day of deadly fighting against suspected rebels in the north of the country, saying that its aim is to "save" civilians from the opposition fighters.
Airstrikes and artillery fire were used by the military in battles on Saturday, with 17 Houthi fighters, who belong to the Zaydi branch of Shia Islam, and six government troops killed, an official from Amran province said.
Saturday's fighting took place closer to Sana'a, the capital, than in any other battles since fighting began on Tuesday.
The fighting has forced thousands of civilians to leave their homes over the past week, the local government official said.
'Annihiliating civilians'
Abdul-Malik al-Houthi, one of the leaders of the Zaydis, said on Saturday that the government's campaign was "a crime that is annihilating civilians."
Al-Houthi also said that none of his followers had been killed during the attacks.
The military offensive was ignited after the sect claimed to be gaining greater control of the northern Saada province, which borders Saudi Arabia, from government troops.
The government has warned that the fighters should meet its ceasefire conditions or face an "iron-fist".
Fighting between the Houthis and the military has left hundreds of soldiers and fighters dead since 2004.
Tensions have been rising between the Houthis and the army in Saada since last July when President Ali Abdullah Saleh declared the conflict over.
The authorities have accused the Houthis of trying to reinstall the rule of imams, toppled by a republican revolution in northern Yemen in 1962.
The fighters say they are defending their villages against government oppression.