Saudi Arabia and Iran fight for Africa's loyalty
Sudan made headlines this week when it became the first African state to cut diplomatic ties with Iran following the attack on Saudi Arabia's embassy in Tehran, as tension escalated over the Saudi execution of Shia cleric Nimr al-Nimr for terror-related offences.
It was joined by Djibouti and Somalia, while Egypt condemned the attacks without going as far as severing diplomatic ties.
What stands out in Sudan's case is how quickly its relations with mainly Shia Iran have deteriorated.
The two nations were strong military allies in the 1990s and 2000s, with Iran providing arms and training to the African nation.
But relations deteriorated when in 2014 Sudan, the only African state governed by a Sunni version of Islamic law, expelled an Iranian diplomat for promoting Shia Islam in the country.
'Seeking Saudi petro-dollars'
In the rivalry between Sunni Saudi Arabia and Iran for supremacy in the Islamic world, Sudan is now firmly in the Saudi camp. Its troops are part of the Saudi-led campaign fighting Shia groups in Yemen.
However, to cut diplomatic ties is still unusual. It seems that Sudan - which is not at all a heavyweight in international politics - wants to show how far it is willing to go to demonstrate loyalty to the Gulf kingdom.
Sudan's economy has suffered since the oil-rich south seceded in 2011, and it is hoping that Saudi petro-dollars will help it rebuild its economy.
Somalia is also in dire need of investment following more than two decades of conflict, including the current insurgency by the al-Qaeda-linked al-Shabab group.
Its authorities recently arrested two Iranian men in what was seen as a warning to Iran not to try to propagate Shia Islam in a country where the overwhelming majority of people are Sunni Muslims.
The Saudis have been generous in investments, and funding Islamic projects in various African countries.
It is, therefore, not surprising that Saudi Arabia announced that more than half of the members of the 34-nation Islamic Military Alliance it had formed to fight militant Islamist groups were African states.
It listed Nigeria - Africa's biggest oil producer and most populous state, which has been hit by an insurgency led by the Boko Haram group - as a member.
But Nigeria, according to a Reuters news agency report, denied it had joined the alliance.
The West African state is unlikely to take sides. It has a significant Shia population, and their main representative, the Islamic Movement of Nigeria (IMN), is backed by Iran.
The IMN is campaigning for an Iranian-styled Islamic republic in Nigeria, and has recently been involved in confrontations with the military.
According to human rights groups, about 300 of its members were killed by soldiers last month after the military accused the IMN of trying to kill army chief of staff Lt Gen Tukur Buratai. The military denied killing anyone.
The alleged killings - along with the detention of IMN leader Ibraheem Zakzaky - caused anger in the Shia world, with Iran lodging a diplomatic protest with the Nigerian government.
Nigeria's President Muhammadu Buhari - a Sunni Muslim - will not want to worsen tensions with Shia, especially when his troops are battling to end the insurgency by Boko Haram, a Sunni group linked to the so-called Islamic State (IS).
Nigeria is more likely to stand back and call for a peaceful resolution to the dispute between Saudi Arabia and Iran.
Other African countries, especially those which do not have Sunni Muslim majorities, are likely to do the same.