The Gambia's leader Yahya Jammeh will step down and leave the country, his elected successor says.

Adama Barrow made the announcement on Twitter, after hours of talks aimed at persuading Mr Jammeh to recognise the result of the presidential election.

West African nations have deployed troops in The Gambia threatening to drive him out of office by force.

Mr Barrow has been in neighbouring Senegal for days. He was sworn in in the Gambian embassy there on Thursday.

His legitimacy as president has been recognised internationally, after he won last month's elections.

Mr Jammeh was given an ultimatum to leave office or be forced out by UN-backed troops, which expired at 16:00 GMT on Friday.

The deadline was set by the Economic Community of West African States (Ecowas), a regional grouping backed by the United Nations.

The presidents of Guinea and Mauritania were locked in talks with Mr Jammeh for hours on Friday negotiating his future.

But the motorcade for the delegation of West African leaders was later seen leaving Gambia's presidential residence, according to Reuters news agency.

It was not immediately clear if Mr Jammeh was inside one of the dozens of vehicles.

Mr Jammeh's term expired at midnight on Wednesday - but, while still president, he engineered a parliamentary vote to extend his presidency. As Mr Barrow has already been sworn in, the country could be said to have two presidents at the same time.

Ecowas said that its forces, from Senegal and other West African countries, had encountered no resistance after entering The Gambia.

After first accepting defeat in the election he reversed his position and said he would not step down. He declared a 90-day state of emergency, blaming irregularities in the electoral process.

The electoral commission accepted that some of its early results had contained errors but said they would not have affected Mr Barrow's win.

Mr Jammeh had said he would stay in office until new elections were held.