Violence is escalating in Ethiopia, where a leader once lauded internationally for his reform agenda and forging peace with neighboring Eritrea faces the specter of civil war.

This month, long-simmering tensions between Prime Minister Abiy Ahmed’s government in Addis Ababa and leaders from the country’s northern Tigray region spilled into the open. Tigrayan forces and the national military have clashed, and Amnesty International has recorded evidence of an alleged massacre of civilians. Hundreds of people have been reported dead. Tens of thousands have fled as refugees to neighboring Sudan.

On Sunday, the Ethiopian government called on Tigrayan forces “to surrender peacefully within 72 hours, recognizing that you are at the point of no return.”

The United Nations human rights office has warned that “there is a risk this situation will spiral totally out of control.” Civilians who fled the fighting and spoke to The Washington Post from Sudan described terrifying scenes of mass violence. One said government troops were “killing people madly.”

On Thursday, 17 U.S. senators sent a letter to Secretary of State Mike Pompeo asking him to “engage directly” with Abiy and “continue pressing all parties to agree to an immediate cease-fire, the de-escalation of tensions, protection of civilians, humanitarian access, and respect for international humanitarian law.”

What set off the conflict?

In early November, Abiy said that Tigrayans had attacked a national military base. He responded by sending troops to the region, which is governed by the Tigray People’s Liberation Front (TPLF) — a political party that once held major influence across the country. In a televised broadcast days later, Abiy announced that the Ethiopian military had bombed Tigray, destroying weaponry near the regional capital of Mekele.

Several days later, hundreds of people may have been killed in a knife-and-machete attack in the town of Mai-Kadra, according to Amnesty International. It was not immediately clear who was responsible.

“We have confirmed the massacre of a very large number of civilians, who appear to have been day laborers in no way involved in the ongoing military offensive,” Deprose Muchena, the human rights watchdog’s East and Southern Africa director, said in a statement.

The group demanded both sides prioritize civilian safety and called on the government to restore communication to the region, which was reportedly cut off in early November.

On Nov. 14, Tigrayan forces fired missiles at targets in Eritrea.

Tigrayan regional president Debretsion Gebremichael has alleged that Eritrea sent troops and tanks over the border into Tigray to support the Ethiopian government, telling Reuters the rockets were retaliation. Reuters reported that he did not provide evidence to back up his allegations.

The escalation in hostilities has spurred a mass exodus from parts of the region.

Abiy wrote on social media Nov. 16 that the Ethiopian government is prepared “to receive and reintegrate our fellow Ethiopians fleeing to neighboring countries.” The next day, he said Ethiopian forces will move ahead with what he described as “the final and crucial” phase of their military operation.

On Nov. 19, the Ethiopian military chief accused World Health Organization Director General Tedros Adhanom Ghebreyesus, who previously served as a minister in Ethiopia’s government as a member of the TPLF, a criminal, claiming he is helping to arm the Tigrayan fighters. He did not offer evidence of his claims.

“I am on only one side, and that is the side of peace,” Tedros said in a statement.

On Monday, Ethiopian state-run media reported that Tigrayan forces had destroyed an airport in Axum, an ancient town in Tigray.

Why is this happening now?

Ethiopian Prime Minister Abiy Ahmed said Nov. 17 that the three-day ultimatum for Tigrayan leaders to surrender has expired. (Reuters)

Tensions had long been brewing among Abiy and leaders from the TPLF, which has seen its national authority dwindle since Abiy took office in 2018.

As prime minister, Abiy dismantled the long-standing ruling coalition, led for years by the TPLF, and created the new Prosperity Party.

Jason Mosley, a research associate at Oxford University’s African Studies Centre, said the move essentially “created a situation where [the TPLF] either had to join the Prosperity Party and submit to his program, or not, in which case they were out.”

It opted not to join.

Abiy won the 2019 Nobel Peace Prize in large part in recognition of his efforts to normalize relations with Eritrea, which shares a border with Tigray.

Eritrea, an extremely closed-off country, was once a part of Ethiopia but gained independence in 1993 after a 30-year struggle. From 1998 to 2000, Ethiopia and Eritrea fought in a war that left tens of thousands dead. The two countries remained enemies for the next 18 years.

When Abiy’s government postponed this year’s elections, citing coronavirus concerns, Tigrayan officials opposed the move and held their election anyway. Abiy refused to recognize results from the September vote, adding to hostilities. The postponement gave both sides grounds to discount the other. “They can both declare each other illegitimate,” said Payton Knopf, a senior adviser at the U.S. Institute of Peace.

In October, Ethiopian lawmakers approved a plan to withhold federal funding for Tigray, further inflaming the tensions.

What does this mean for regional security?

Debretsion Gebremichael, the leader of Ethiopia's rebellious Tigray region, said his forces fired rockets at the Eritrean capital Asmara on Nov. 14. (Reuters)

If conflict escalates further, it could destabilize the region and lead to mass displacement, Knopf said.

Neighboring Sudan, where more than 33,000 people have already fled, is going through a fragile transition and an economic crisis. In a worst-case scenario, Ethiopia could now experience “what could be one of the largest refugee exoduses we’ve ever seen,” Knopf said.

The Tigrayans’ decision to launch missiles at Eritrea also added an international element to the conflict.

Mosley said he doesn’t believe the Eritrean government will want to enter the conflict directly. “But if the Eritrean military gets involved,” he said, “it’s really bad for Abiy, because it makes him look like he needs the Eritreans to control his own territory.”

About 96,000 Eritrean refugees live in Tigray, sparking fears they could be displaced again.

How is the international community responding?

This week, Babar Baloch, a spokesman for the U.N. High Commissioner for Refugees, said the agency views the situation as a “full-scale humanitarian crisis.”

In statements this month, the U.S. State Department has also urged de-escalation of the crisis and called for communication to be restored in the region.

In their Thursday letter to Pompeo, the 17 U.S. senators urged that the United States get involved more directly in efforts to restore peace to the region. The letter cited major concerns over the humanitarian crisis and escalating violence, noting that in addition to the many Ethiopians displaced in recent days, the conflict also “poses a direct threat to hundreds of American citizens, journalists, and aid workers in the Tigray region and surrounding areas.”

Sen. Chris Van Hollen (D-Md.), who wrote the letter, said in a phone call with The Post that he has “been concerned about the lack of engagement at the highest levels, especially with respect to Secretary Pompeo.”

“This is not about pointing fingers, this is about stopping a growing humanitarian crisis,” he said. “The U.S. has strong interests in Ethiopia and the region, and it makes sense for a secretary of state to play more of a leadership role.”

“We’ve seen a couple of tweets, but that’s not a substitute for personal diplomacy,” Van Hollen added.

Foreign countries are also pushing Abiy to pursue peace talks, Reuters reported Monday. Officials in neighboring countries, including Uganda and Kenya, continue to call for dialogue to resolve the conflict.