A drone strike in a busy market in the disputed region of Abyei has killed more than 150 people, according to local officials.

South Sudanese officials blamed Sudan's military for the attack, without providing evidence, amid the long-running civil war between the Sudanese Armed Forces and the Rapid Support Forces (RSF) militia, which is reportedly active in the Abyei area.

The special UN mission in Abyei warned in May that the RSF's presence in the resource-rich region had put residents in additional danger, and risked intensifying the older territorial dispute between Sudan and the world's newest sovereign state, South Sudan.

What do we know about the drone strike?
According to local authorities, the attack hit the busy Amiet Market at around midday on Monday.

Yohana Akol Ngor, the caretaker information minister in Abyei, told Reuters news agency on Tuesday that the death toll had more than doubled, reaching at least 153 compared to a stated figure of 73 the previous day.

He said that Sudan's military was responsible for the attack but did not provide evidence. Akol Ngor said around 8,000 people had been displaced by the bombing.

South Sudan's Foreign Ministry also blamed the Sudanese army and said the drone struck multiple locations around the busy market.

One of these, judging by witness accounts, was a fuel depot — and this led to a large fire that proved difficult to bring under control overnight and was still ablaze on Tuesday.

South Sudan said it had summoned Sudan's ambassador to protest and urged Sudan to "refrain from any actions that endanger civilian lives and property."

Medical charity Medecins Sans Frontieres (MSF), or Doctors Without Borders, said that its staff was treating some 20 wounded people at the nearby Ameth Bek hospital.

"So far we received over 20 patients, including several critical cases. Patients with burns were also admitted," said Dr. Christian Lindauer, MSF's medical activities manager at the hospital.

What's the backstory of Sudan, South Sudan and Abyei?
The oil-rich Abyei region's status was not resolved by the 2005 peace agreement that broadly ended decades of civil war in Sudan.

It was also not settled in 2011 when South Sudan became an independent country.

A referendum was planned but never materialized, stalling over disputes on who should be allowed to vote. This left Abyei in a state of limbo, jointly administered and with an interim UN security force on site for 15 years.

The region's majority Ngok Dinka population favors joining South Sudan, while Misseriya nomads who use its pastures favor Sudan.

Amiet Market, the site of the attack, is an important trading hub for both communities.

The unstable region has also experienced intercommunal violence in recent years between Ngok Dinka and neighboring Twic Dinka communities and is home to other armed militias.

How does this fit into Sudan's army's war with the RSF?
The April 2023 outbreak of fighting between the Sudanese Armed Forces and the Rapid Support Forces paramilitary — which has turned into a conflict with fairly entrenched battle lines, putting Sudan into a de facto state of partition — is increasing tension in the already-strained region.

Abyei borders South Kordofan state in Sudan, which has become a major center of fighting in the war.

Sudan's military alleges that the RSF is also operating out of Abyei. The United Nations Interim Security Force for Abyei (UNISFA) issued a similar statement in May.

Officials in Abyei and South Sudan dispute this, however.

"We remain alarmed by the relentless drone attacks across Sudan, as well as the damage they are causing to critical infrastructure — these attacks are taking a devastating toll on communities already struggling with the consequences of more than three years of conflict," UN spokesperson Stephane Dujarric told reporters in New York on Tuesday when asked about the attack.