The Yale School of Public Health's Humanitarian Research Lab (HRL) said analysis of satellite imagery and open-source data shows activity "consistent with military assistance to the RSF" at an Ethiopian base in Asosa, in the Benishangul-Gumuz region, between late December 2025 and late March 2026.

The paramilitary group, which has been at war with Sudan's army since April 2023, was accused last month by the Sudanese military of launching drone attacks "from inside Ethiopian territory", the first public allegation of Ethiopian involvement in the conflict.

Ethiopia has denied the claim and has also rejected allegations that it is hosting RSF camps.

Yale's HRL has used remote sensing data and satellite imagery to monitor the war since it began.

Its researchers said their findings "represent clear visual evidence over a five-month period" that RSF attacks on Sudan's southeastern Blue Nile State were being launched from within Ethiopia.

The researchers identified repeated arrivals of commercial car carriers at the base unloading vehicles known as "technicals", light pickup trucks commonly used by armed groups.

HRL said these vehicles do not match those normally used by the Ethiopian military and have been observed supplying RSF units operating in Sudan's Blue Nile state.

According to the report, some of the vehicles were later fitted with gun mounts "capable of holding heavy machine guns".

Objects consistent with 50-calibre weapons were also observed nearby, the report said.

HRL added that similar vehicles later appeared in open-source images from fighting around Al-Kurmuk, a strategic Sudanese border town roughly 100 kilometres (62 miles) by road from Asosa.

Recent fighting has intensified around Al-Kurmuk, a key army position.

This year, an estimated 28,000 people were displaced by fighting in Blue Nile, including more than 10,000 from Al-Kurmuk alone.

Control of the state is divided between Sudan's army and RSF allies from the Sudan People's Liberation Movement-North (SPLM?N), led by Abdelaziz al-Hilu.

The paramilitaries have recently claimed victories in the area.

The Yale lab also documented increased logistical activity at the Asosa base, including the arrival of shipping containers, fuel tanks and tents capable of housing up to 150 people.

White armoured vehicles inconsistent with Ethiopian military markings were also seen, alongside frequent movements of non-military transport trucks.

Separately, satellite imagery showed significant expansion at Asosa airport, including "a new hangar and concrete pad" and defensive fighting positions.

Imagery previously analysed by AFP has shown significant development at the airport, which previously served as a drone base.

The RSF last year brought thousands of fighters into Ethiopia, an RSF source and an army source told AFP.