Qatar's emir started a visit to Sudan on Wednesday at a time of strained ties with his country's Gulf neighbours over its perceived support for the Egypt-based Muslim Brotherhood.
Sheikh Tamim bin Hamad Al-Thani was greeted at Khartoum airport by Sudan's President Omar al-Bashir, at the start of what an analyst called a meeting of two regionally-isolated regimes.
The two were to hold talks at a conference centre along the Blue Nile.
Sheikh Tamim's stop, planned to last about six hours, coincides with unprecedented tensions between Doha and other Gulf states over the widely-banned Muslim Brotherhood.
The Sudanese regime, which took power 25 years ago in an Islamist-backed coup, is essentially based on support from the Brotherhood, said Safwat Fanous, a political scientist at the University of Khartoum.
He told AFP that the emir's visit appears aimed to "break the isolation" of Qatar from its Gulf neighbours and Egypt.
Energy-rich Qatar has been a key backer of Sudan's cash-strapped government, and Khartoum's foreign ministry said the emir's visit came at the invitation of Bashir.
Sudanese officials last month said Qatar was providing $135 million in support for Sudan's rich but under-developed archaeological heritage.
Qatar also hosted talks which led to the 2011 Doha Document for Peace in Darfur between Khartoum and rebel groups in the western region of Sudan.