Sudan's government says it has suspended any involvement in peace talks mediated by the East African regional body, Igad.
It had been trying to get the army and the rival paramilitary Rapid Support Forces (RSF) to negotiate an end to the nine-month civil war.
The foreign ministry said it had suspended dealings with Igad after the regional group added Sudan to the agenda of a meeting and invited the RSF leader Mohamed Hamdan Dagalo to attend.
He has just visited several African countries in a bid to drum up political support.