Mexican police have made their first arrests after clashes in which 26 farmers were shot dead in an ambush in mountainous Oaxaca province.

Police say they have detained 14 people, although they have not yet charged them.

They are looking for as many as 50 men or more who they believe took part in the ambush on a remote road on Friday as the farmers were returning home to their village of Santiago Xochiltepec.

The gunmen stopped the farmers' truck, ordered the driver out and then raked the back of the truck with gunfire.

Survivors

Police say at least two people survived by playing dead as the gunmen picked their way through the bodies.

The motive is unclear. A similar massacre in the area four years ago was sparked by a land dispute.

The governor of Oaxaca sent more than 200 police and investigators to the village immediately after the attack to find the culprits and prevent reprisals.

BBC Central America correspondent Nick Miles says a recent influx of drug traffickers has made guns readily accessible.

Our correspondent says this mountainous and deeply impoverished part of Mexico is rife with disputes over land and water rights that often spill over into violence, though never in recent years with such drastic consequences.

The obvious fear of the authorities is that the troubles could escalate with family members of the victims trying to carry out reprisals against those they believe were behind the massacre.