NAIROBI, Kenya (AP) — Tensions over the deadly conflict in Ethiopia are spreading well beyond its cut-off Tigray region, as the federal government says some 150 suspected “operatives” accused of seeking to “strike fear and terror” throughout the country have been detained.

The new statement says the suspects “happen to be ethnically diverse,” but concerns remain high among ethnic Tigrayans amid reports of being singled out by authorities.

The statement comes as rallies are expected Thursday in support of the federal government’s military offensive in the northern Tigray region against a regional government that Nobel Peace Prize-winning Prime Minister Abiy Ahmed and his government regard as illegal.

Close to 10,000 Ethiopian refugees have already fled the weeklong conflict into neighboring Sudan, where local authorities are already warning they are overwhelmed. They are preparing for up to 200,000 arrivals.

Ethiopia’s prime minister has rejected international pleas for negotiation and de-escalation, saying that cannot come until the Tigray People’s Liberation Front ruling “clique” is removed and arrested and its heavily stocked arsenal is destroyed.

What appeared to be a sudden slide toward civil war has been months in the making. Abiy after taking office in 2018 announced sweeping political reforms that won him the Nobel but marginalized the TPLF, which had dominated Ethiopia’s ruling coalition. The TPLF later left the coalition and in September held a local election in defiance of the federal government.

Each side now regards the other as illegal, and each blames the other for starting the fighting.

Communications and transport links remain severed in the Tigray region, making it difficult to verify claims, while the United Nations and others warn of a looming humanitarian disaster as food and fuel run short for millions of people.

The effects of the conflict risk drawing in Ethiopia’s neighbors, notably Sudan, whose leaders are under pressure from the international community, Ethiopia’s federal government and now the government of Eritrea, which the TPLF accuses of joining the fighting at Ethiopia’s request.

Experts fear that the Horn of Africa, one of the world’s most strategic regions, could be destabilized despite Abiy’s past peacemaking efforts.