ADDIS ABABA (Reuters) - Police in Ethiopia arrested the disgraced former head of the eastern Somali region on Monday on charges of human rights abuses and stoking deadly ethnic clashes, the attorney general’s office said.

Prime Minister Abiy Ahmed, presiding over democratic reforms in the African nation of 100 million, said on Saturday rights abuses committed in the region “defied belief” and included torture, rapes and killings.

The region’s administrator, Abdi Mohammed Omer, was forced to resign on Aug. 6 after violence broke out in the provincial capital Jijiga.

At least 20 people died and thousands fled Jijiga as mobs looted properties owned by ethnic minorities and burned down several Ethiopian Orthodox churches.

The central authorities said the unrest in the region had been triggered by local officials fearing arrest on human rights abuse charges. [L5N1UV0ES]

On Monday, Federal Police “apprehended Abdi Mohammed Omer at his home in Addis Ababa,” state-run Ethiopian Broadcasting Corporation said, citing the Federal Attorney General’s Office.

“Crimes he committed include, among others, human rights abuses and stoking disputes along ethnic and religious lines,” it said, adding that other officials were also sought by police.

Rights groups have routinely accused Abdi’s administration of abuses such as torture, while some witnesses claimed he had ordered paramilitary raids on civilians in neighboring Oromiya province after ethnic clashes there last September.

The government fired senior regional prison officials last month over accusations of torture. Abiy on Saturday described cases in which prisoners had been put into cells with lions, hyenas and leopards to force them into confessing.

The region has been plagued by violence for the last three decades, in which the government fought the secessionist Ogaden National Liberation Front before the group declared a unilateral ceasefire this month in the wake of reforms.[L5N1V30CE]

The region holds four trillion cubic feet of oil and gas reserves, government estimates show. China’s GCL-Poly Petroleum Investments has been developing two gas fields there since 2013.