Alassane Bala Sakandé, who is also the leader of the former ruling party, was arrested by police at his home early on Sunday morning.

He was released without charge in the evening after hours of interrogation in the capital Ouagadougou, local broadcaster Radio Omega reported.

"He stands reproached for remarks he made at the news conference of his party, the People's Movement for Progress held on 24 March," the AFP news agency had earlier quoted his lawyers as saying.

Mr Sakandé said that the former president was not under house arrest but in detention due to the difficult conditions he had allegedly been subjected to.

The former president was deposed in January and has been held under house arrest since then.

The West African regional bloc Ecowas, which has threatened to impose further sanctions on Burkina Faso, has demanded his unconditional release.