Civil aviation authorities in Sudan have suspended flights to and from the main airport in the capital, Khartoum.
Flight activities will be suspended until Saturday, a statement posted on Facebook said.
Anti-coup protesters took to the streets on Tuesday, a day after deadly clashes.
Earlier in the day coup leader Gen Abdel Fattah al-Burhan said the military seized power on Monday to prevent "civil war".
He added that the deposed Prime Minister Abdalla Hamdok was being kept at the general's house "for his own safety" and would be allowed home soon.