Kenyan President Mwai Kibaki on Tuesday ordered the army to be deployed to a restive northern area where gunmen massacred 42 police officers in a weekend ambush, the deadliest in the country's history.

Kenya's National Security Council, chaired by Kibaki, authorised the rare deployment of the army to support police in "apprehending the bandits and recovering stolen animals and arms", a presidential statement said.

Police say that 42 policemen in all were killed as they hunted cattle thieves on Saturday in Baragoi, a remote district in Kenya's arid north, although the official toll still stands at 32 dead.

At least a dozen body bags were seen by an AFP reporter being offloaded from an airplane in Nairobi, and Kibaki offered his condolences to the families of those who had died.

Angry relatives gathered Tuesday to receive the bodies of those killed.

"Someone needs to tell me how he died... he was not in a war zone, he was slaughtered like an animal," said Amina Dhullow, whose 28-year old son was killed in the attack.

Troops will be deployed in "Samburu county and other areas" the statement added, which "condemned the heinous act".

The group of rustlers police were pursuing were already suspected of killing 13 people in a raid on October 30.

Police set out after the rustlers when a deadline for the return of the cattle expired.

"Everything will be done to ensure the culprits are apprehended and dealt with in accordance with the law," it said, adding that "peace, reconciliation and disarmament exercises" would take place.

Cattle theft and the ensuing clashes between rival pastoralist groups claim dozens of lives every year in arid northern Kenya. However, it is rare for police officers to be attacked by rustlers.

The violence is not believed to be linked to politics, but it raises concerns over security and a lack of police capacity in volatile areas ahead of elections due to take place in March.

Elections five years ago descended into deadly post-poll killings that shattered Kenya's image as a beacon of regional stability.

Elsewhere in Kenya, in the southeast Tana River region, inter-communal violence claimed more than 100 lives, including those of several police officers, in August and September.

Kenya has also suffered a wave of grenade attacks, often blamed on Islamist supporters of Somalia's Al-Qaeda-linked Shebab insurgents and sometimes aimed at police targets. Police have also launched a crackdown on a coastal separatist movement.