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.