Yahya Jammeh of Gambia
Yahya Jammeh, president of The Gambia for 22 years, has announced he would no longer accept defeat in a recent ballot, plunging the West African nation into turmoil and demanding fresh polls.
Ms Sirleaf, who currently heads the Economic Community of West African States (ECOWAS), was headed to The Gambia but her plane was not allowed to land, amid a heavy deployment of security forces.
Ahead of Mr Jammeh's statement, the atmosphere tightened in Banjul, and today troops and police were on the streets and barricades were erected at strategic places, according to an AFP correspondent.
Mr Jammeh, speaking on state television late last night, said an investigation into the 1 December vote had revealed "unacceptable errors" from electoral authorities, and he would no longer concede to his opponent Adama Barrow.
Senegal's foreign ministry criticised Mr Jammeh's change of heart, saying it "rejected and condemned" his remarks and was "surprised" by them.
"Senegal demands that the outgoing president unconditionally respect the democratic choice freely expressed by the Gambian people," the ministry said in a statement.
It urged the authorities to "organise a peaceful transmission of power and ensure the security and physical integrity of the newly elected president," referring to Mr Barrow.