More than 1,000 gunmen from South Sudan have killed 28 people and kidnapped 43 children in Ethiopia, a government official has said. The raids occurred in the Gog and Jor areas of the Gambella region, which borders South Sudan's Boma region, on Sunday and Monday (12-13 March).

The attackers are believed to belong to the Murle ethnic group.

"Murle bandits carried out the attack. They fled along with 43 children," Chol Chany, a regional government spokesman, told Reuters.

He added that the Ethiopian army was pursuing the attackers, who are not yet believed to have crossed back into South Sudan.

Similar incidents occurred in March and April 2016, when gunmen thought to be Murle stormed several villages across Gambella killing at least 208 people and abducting some 160 children, the majority of whom have since been reunited with their families.

Members of the Murle have been blamed for previous raids in Gambella in which they stole cattle and kidnapped children to raise as their own. Last year, the gunmen targeted people from the Nuer tribe, a group to which South Sudan's rebel leader Riek Machar belongs.

The Murle group is close to the Dinka tribe, from which South Sudanese President Salva Kiir hails. Some believe the attacks might be related to the ongoing conflict in South Sudan that has pitted Nuer against Dinka and resulted in the death of thousands of people.

Gambella region hosts hundreds of thousands of South Sudanese people who fled the conflict, which erupted in 2013 when Kiir fired Machar, who was then the country's vice-president.