Image copyright PA Image caption Sudanese planes take off from Khartoum’s airport as a security convoy deployed
It’s an unusual sight – three presidential helicopters landing at the same airport.
Sudanese and African leaders have been attending the African Union summit in the South African city of Durban, some 3,000km (1,864 miles) away.
But, during President Omar al-Bashir’s visit, there has been a security alert involving the President and his entourage.
At least 10 people were killed on Tuesday when fighting erupted between security forces and Islamic extremists in the capital, Khartoum.
Bashir is facing charges of war crimes at the International Criminal Court.
Unnamed security sources were quoted by AFP news agency as saying one helicopter had landed at the National Assembly and another at the defence ministry.
A third helicopter had landed outside the presidential palace.
The sources said several hundred security personnel had been deployed and aircraft deployed as a security alert was declared.
No details were immediately available on casualties.
Some soldiers had earlier fired shots in the air to try to drive civilians from the area before they were dislodged, according to the military.
Image copyright Getty Images Image caption President Bashir is facing charges of war crimes at the International Criminal Court
No further details of the security operation were available, however reports say a number of roadblocks had been set up.
The state news agency, SUNA, reported that a conference hall at Khartoum’s National Assembly had been temporarily closed.
Sudan’s ambassador to Nigeria, Osama Kana, was quoted as saying that the Sudanese military was carrying out raids in Darfur to secure the country’s borders.
On Friday, Mr Bashir said in an interview with the BBC that the Sudanese military had taken over the streets in “large numbers” for “security”.
The government announced a state of emergency in April 2014 after an attack on a Red Cross convoy that killed 11 people.
Mr Bashir was in South Africa as part of an African Union summit that was scheduled to last three days.
The AU was holding a special summit on the situation in South Sudan, an east African country embroiled in a civil war since 2013.
The war has led to widespread suffering among its population and forced nearly three million people to flee their homes.
The unrest started after the ousting of the then president, Salva Kiir, by rival Riek Machar, his deputy, who later retired from his post.
Mr Machar, who is trying to rebuild his peace deal with Mr Kiir, was brought under house arrest by Mr Bashir’s government in 2016.
Human Rights Watch (HRW) said at least 1,500 people had been killed in security operations against his SPLM-North faction in August 2016.