The Sudanese government suspended ties Tuesday with the east African regional bloc trying to mediate between the country’s army and a rival powerful paramilitary force, accusing the body of violating Sudan’s sovereignty by inviting the paramilitary leader to an upcoming summit.

The army, headed by Gen. Abdel-Fattah Burhan, and The Rapid Support Forces, commanded by Gen. Mohammed Hamdan Dagalo, have been fighting for control of Sudan since April. Long standing tensions erupted into street battles concentrated in the capital but also in other areas including the western Darfur region.

In a statement, The Sudanese foreign ministry — which is aligned with the army — said the move is a response to IGAD for inviting Dagalo without previous consultation, which it said was a “violation of Sudan’s sovereignty.” The 42nd IGAD summit is set to take place in Kampala, Uganda, on Thursday.

IGAD did not immediately respond to the foreign ministry announcement. Dagalo confirmed last week on social media that he received an invitation from IGAD.

The eight-member bloc is part of mediation efforts to end the conflict, along with Saudi Arabia and the United States which facilitated rounds of unsuccessful, indirect talks between the warring parties as recently as early November. The two military leaders are yet to meet in person since the war broke out.

Tuesday’s announcement comes one week after Dagalo finished a tour of Africa, where he met with government officials in Uganda, Djibouti, Ethiopia, Kenya, South Africa and Rwanda.

Over the past two months, the RSF has appeared to take the upper hand in the conflict, with its fighters making advances eastwards and northwards across Sudan’s central belt.

The United Nations says at least 12,000 have been killed in the conflict. Right groups have accused both sides of war crimes.

The countries that make up IGAD include Djibouti, Eritrea, Ethiopia, Kenya, Somalia, South Sudan, Sudan and Uganda.