Since April 2023, the conflict between the former allies has killed tens of thousands and displaced millions more.

The RSF, historically a powerful infantry, has conquered vast landlocked territories in the west and south, relying on supply routes through Sudan's neighbours.

While international attention is currently focused on the war in the Middle East, the fighting in Sudan shows no signs of resolution.

Here, AFP outlines the main routes and alliances feeding the war:

- UAE -

Khartoum accuses the RSF of being a "proxy" for the United Arab Emirates.

Abu Dhabi denies arming the RSF, despite evidence presented in numerous international reports.

US sanctions imposed on some RSF commanders note specifically their financial ties to the UAE.

Last year, former White House advisor Cameron Hudson told the UN Security Council that the UAE had built "an extensive air bridge" to the RSF, using its "client states" including Chad, Libya, the Central African Republic and South Sudan.

"The Emirates has multiplied its routes and channels" into the country, according to French researcher Roland Marchal. Diplomatic and humanitarian sources that AFP spoke to said the same.

According to a report by Critical Threats, Abu Dhabi has poured billions of dollars into the Horn of Africa, maximising its access to arable land, gold deposits and the Red Sea.

To counter it, Saudi Arabia, Egypt and Turkey have cultivated an opposing sphere of influence.

- Egypt -

Sudan's northern neighbour and former colonial power Egypt openly supports army chief Abdel Fattah al-Burhan -- in power since a 2021 coup -- as Sudan's only "legitimate" authority.

Cairo denies any military involvement, while openly defending a crucial ally in its conflict over Nile waters with Ethiopia.

In late 2024, the RSF accused Egypt of conducting air strikes and delivering fighter jets.

Again, in September last year, it condemned drone strikes "from a neighbouring country".

According to experts, the paramilitary capture of the western border triangle between Sudan, Egypt and Libya in June was seen in Cairo as a major national security threat.

Egypt has since referred repeatedly to "red lines" and that it will take "all necessary measures" to protect Sudan's national security.

According to two Western diplomats and local media reports of destroyed desert convoys, the Egyptians have in recent months disrupted RSF supplies through the border.

Satellite imagery analysed by AFP shows aircraft corresponding to Turkish-made Bayraktar drones appearing on several occasions in recent months at an airbase in Egypt's southwestern desert.

- Libya -

Eastern Libya strongman Khalifa Haftar has helped the UAE funnel fuel, weapons and mercenaries to the RSF.

Last year, the Sudanese army accused his forces of direct involvement in the RSF takeover of the border triangle.

According to three Western diplomats, Egypt, with the help of Saudi Arabia and Turkey, has stepped up pressure on Haftar in recent months to halt the eastern Libya supply line.

In January, his forces closed the Kufra Airport -- described by experts as a key RSF air bridge -- for "maintenance", which analysts say was not necessary.

It was reopened three weeks later.

Two Egyptian security sources have told AFP that Cairo considers the RSF's border triangle route successfully cut off.

- Chad -

According to International Crisis Group expert Charles Bouessel, pressure on Libya has led to a "clear resumption of UAE deliveries" through Chad's capital N'Djamena, despite higher logistical costs.

In 2024, several investigations, including by UN experts, found evidence of Emirati weapons transfers through the Amdjarass airport, near the border with Sudan.

The area is home to the Zaghawa, a transnational ethnic group, which the RSF has targeted with "acts of genocide" in Darfur, a UN probe found last month.

President Mahamat Idriss Deby, whose father was Zaghawa, has come under fire including by his own clan for helping the UAE arm the RSF.

Chad last month closed its border with Sudan.

- Ethiopia -

Khartoum this month said that drone attacks on Sudan have "originated from Ethiopian territory" -- the first direct accusation against Addis Ababa, also a close ally of the UAE.

Last month, Egypt at the Security Council referred to "documented reports of one of Sudan's neighbours setting up camps to train and arm" the RSF.

In October, army-allied militia leader Mostafa Tambour told Al Jazeera that the RSF "has established camps in Ethiopian territory" to attack the Blue Nile state.

Ethiopia has denied harbouring RSF camps.

Just across the border from the state's paramilitary stronghold, satellite imagery analysed by AFP shows significant development in Ethiopia's Asosa airport -- previously used to launch drones.

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