Guinean special forces staged a coup on Sunday, arresting the president, in the latest political upheaval to roil the impoverished west African country.

"We have decided, after having taken the president, to dissolve the constitution," said a uniformed officer flanked by soldiers toting assault rifles in a video sent to AFP.

The officer also said that Guinea's land and air borders have been shut and the government has been dissolved.

Another video sent to AFP by the putschists showed a rumpled-looking President Alpha Conde sitting on a sofa, surrounded by troops. He refused to answer a question from one soldier about whether he was being mistreated.

Guinea -- one of the world's poorest countries despite boasting significant mineral resources -- has long been beset by political instability.

Earlier on Sunday, residents of the capital Conakry's Kaloum district, the government quarter, reported hearing heavy gunfire.

A Western diplomat in Conakry who declined to be named suggested the unrest may have started after the dismissal of a senior commander in the special forces -- provoking some of its highly trained members to rebel.

AFP was unable to independently confirm this account. Later on, the head of Guinea's military special forces, Lieutenant-Colonel Mamady Doumbouya, appeared on public television, draped in the national flag, and cited government "mismanagement" as a reason behind his actions.

"We are no longer going to entrust politics to one man, we are going to entrust politics to the people," the coup leader said.

"Guinea is beautiful. We don't need to rape Guinea anymore, we just need to make love to her," Doumbouya added.

UN Secretary-General Antonio Guterres condemned the coup in a tweet and called for Conde's immediate release.

The putsch comes amid a long period of political tension in Guinea, first spurred by Conde's highly contested bid for a third presidential term last year.  

The day before the presidential election last year, the military blocked access to Kaloum after an alleged military rebellion east of the capital.

 Conde, 83, also survived an assassination attempt in 2011.

There was initial confusion about Sunday's events, as the government released a statement saying that it had "repulsed" a special forces attack on the presidential palace.

But the reality of the putschists' success set in as the day wore on. The coup plotters announced a so-called national committee for assembly and development, which will be tasked with consulting political and civil society figures on the way forward.

They said the constitution would be rewritten. Doumbouya also told French media "we are holding all of Conakry," and that he had the support of all the defence and security forces.

News of the coup sparked celebrations in some parts of the capital, where hundreds of people applauded the soldiers.

"We are proud of the special forces," said one demonstrator who requested anonymity. "Death to the torturers and to the murderers of our youth".