The government launched an operation to crush rebels in early August
Yemeni officials say 17 Shia rebels have been killed in the latest fighting in the north of the country.
Four other rebels, known as Houthis, were arrested as they fled the battleground in Saada province, the official news agency reported.
The government claimed to have pushed rebels back from a number of positions.
It says the rebels are trying to impose Shia religious law. Rebels say the government is corrupt, beholden to the West and persecuting Shias.
The rebels have accused the government of carrying out air attacks on villages in the region, killing a number of civilians.
The international Red Cross says thousands of people displaced by the fighting in Saada remain in urgent need of assistance.
ICRC spokesman Hicham Hassan told the BBC many people have been forced into tented camps, including pregnant women, children and the elderly, and require better shelter as the weather turns colder.
He also said the Red Cross was unable to reach rural areas caught up in the fighting.
The latest violence follows a brief truce, aimed at allowing in humanitarian aid.