NAIROBI, Kenya (AP) — Abiy Ahmed left Ethiopians breathless when he became the prime minister in 2018, introducing a wave of political reforms in the long-repressive country and announcing a shocking peace with enemy Eritrea.

The young prime minister was cheered as he toured Ethiopia in his feverish first days, including when he visited the powerful Tigray region, whose leaders had dominated the national ruling coalition for decades. The international community, dazzled, showered Abiy with praise. Not even two years after taking power, he was awarded the Nobel Peace Prize.

Now — a year later — Abiy is waging war in Tigray, accusing its forces of a deadly attack on a military base after what he said was a series of provocations. His shine is threatening to wear off as his country’s long-brewing troubles explode onto the world stage, and he rejects international pressure for dialogue.

Abiy contends there's no one to talk to, asserting that the Tigray regional leaders are criminals who recently held an election his government called illegal and that their actions have threatened Ethiopia's sovereignty.

Well over 25,000 refugees have fled the fighting into Sudan, bringing word of vicious attacks by armed forces and even rival ethnic groups.

Abiy on Tuesday vowed a “final and crucial” military offensive as he tries to hold together a nation of 110 million people with scores of ethnic groups, some of which might try to defy him as the Tigray leaders have.

“If Tigray is not solved somehow, I don’t think the situation of the country will be solved,” Mekonnen Gebreslasie Gebrehiwot, who leads an association of ethnic Tigrayans, told The Associated Press from his home in Belgium.

On Tuesday, the Nobel committee said in a statement that it is “deeply concerned” about the situation in Ethiopia, and it called for all parties involved to “end the escalating violence.” The United States, the African Union, Pope Francis and the United Nations secretary-general all have expressed their deep concern and urged a peaceful resolution.

But there is no clear path back to peace in a region that’s seen little of it. “This conflict dashes our hopes for the region,” prominent Horn of Africa citizens wrote in a letter circulated late last week.

For much of the world, Abiy's transformation from peacemaker to war-wager was as swift as his rise to power.

But for months, human rights groups had warned that Abiy’s administration was beginning to embrace the repressive ways of the past, including locking up critics and shutting off the internet.

Even as the Nobel committee awarded Abiy last year, it defended its choice. “No doubt some people will think this year’s prize is being awarded too early,” it said, noting “troubling examples” of ethnic violence. But it believed “it is now that Abiy Ahmed’s efforts deserve recognition and need encouragement.”

For many, Abiy represented a welcome break from the past when he rose to power in one of Africa’s most powerful countries, a key U.S. security ally in the strategic Horn of Africa.

His government welcomed opposition figures home from exile, and released others from prison, including some who had been sentenced to death. He swept through the region, brokering peace, and toured the United States to excited diaspora crowds.

He was seen by many as a unifier, the son of a Christian and Muslim and of mixed ethnic heritage. He surprised Ethiopians by apologizing for the government’s past abuses. He appeared to be drawing from his painful past.

In his Nobel address, the former soldier recalled his fighting experience on the Eritrean border two decades ago. “War is the epitome of hell for all involved,” he said.

But for some, it was hard to miss a warning amid his calls for unity in Ethiopia, where some ethnic groups have pushed hard for more autonomy, sometimes with violence.

Speaking specifically to his countrymen from the Nobel lectern, Abiy said: “The evangelists of hate and division are wreaking havoc in our society using social media. They are preaching the gospel of revenge and retribution.”

He added that Ethiopia and Eritrea made peace because they were the “victims of a common enemy,” which was poverty.

But now Tigray regional leaders assert that Ethiopia and Eritrea have instead found a common enemy in them.

Terrible accounts have begun to emerge from shaken refugees. “These people are coming with knives and sticks, wanting to attack citizens. And behind them is the Ethiopian army with tanks,” said one refugee, Thimon Abrah. “And we’re here, waiting, for any sort of solution.”

Abiy on Monday said his government would welcome, protect and reintegrate those who have fled. But those fleeing are wary of any promises from his government, which they say attacked them. The government has repeatedly denied that.

For Ethiopians at home and in the diaspora, there is anger, sadness and suspicion as the United Nations warns of alarming rhetoric and the targeting of ethnic groups.

Abiy has vowed to limit the conflict to combatants. But he also rejects compromise, promising that the fighting will only end once the region's leaders from the Tigray People’s Liberation Front are arrested and their arsenal destroyed.

“Abiy overreached,” Tsedale Lemma, the editor of the Addis Standard newspaper, wrote last week in The New York Times, calling the prime minister’s sidelining of the region’s leadership his first “cardinal mistake.”

But the official overseeing the new state of emergency in Tigray defended the prime minister’s unyielding stance.

“He faces the very threat to his own nation,” Redwan Hussein told reporters late last week. “The only thing he has to do is to defend it. So if there is a second Nobel Peace Prize, then he has to win it again because he is still salvaging his country.”