South Sudan’s government signed a ceasefire deal with rebel forces on Thursday, in an attempt to stem the bloody violence that has ravaged the world’s youngest country since December 15.

The conflict centers around a power struggle between South Sudan President Salva Kiir and his former deputy Riek Machar, who was fired last July and was recently accused of plotting a coup. It also highlights ethnic tensions in the world’s youngest state, founded only in 2011, as Kiir is an ethnic Dinka, while Machar is from the Nuer tribe.

The ceasefire was signed by the two in Addis Ababa, the capital of Ethiopia, and is to come into effect within 24 hours, reports Al Jazeera. Kenyan President Uhuru Kenyatta and Ethiopian Prime Minister Hailemariam Desalegn began trying to negotiate peace in late December.

Roughly half a million South Sudanese fled their homes during the internecine violence, which the UN estimates has left over 1,000 dead amid atrocities by both sides. The fighting threatened to spiral into an all-out ethnic war.

Reportedly the deal will include a monitoring mechanism to ensure the ceasefire is honored, and will allow unfettered access for aid workers. It also includes an agreement by Kiir to release 11 officials close to Machar who were arrested during the conflict.

Deng Gai, a defector to the rebels who was a general in the army previously, expressed hopes the deal would “pave the way for a serious national political dialogue aimed at reaching a lasting peace in South Sudan.”

Will the ceasefire hold?

A negotiator for Kiir’s government, Nhial Deng Nhial, reported that “what worries us is whether the agreement on the cessation of hostilities will stick [and] the capacity of the rebel group … to stop fighting.”

The ability of the rebels to impose the ceasefire on their forces is in doubt, particularly as a group of Machar’s Nuer ethnicity known as the White Army reportedly is opposed to the peace agreement.

On Thursday, the UN announced it is guarding 76,000 civilians at 8 bases around the country, and that it has received reports that fighting continues in various parts of South Sudan.

In response to the rising violence, the US evacuated its staff from the country on January 3.

Following the recent deal, White House spokesman Jay Carney hailed the agreement as a “first critical step in ending the violence,” expressing anticipation for a full implementation and the start of comprehensive dialogue.

Catherine Ashton, EU foreign policy chief, similarly supported the deal, stating “the killing must end now.”

“This agreement must now be turned to reality and the parties must move immediately to implement in good faith,” remarked Ashton. “The displaced must be able to return home. Humanitarian assistance must reach all in need without obstacle or abuse.”