Gambia's President Yahya Jammeh has declared a national state of emergency one day before the end of his mandate.

In a national TV address, Jammeh said on Tuesday the measure was necessary due to "the unprecedented and extraordinary amount of foreign interference" in last month's presidential vote, which he lost to opposition leader Adama Barrow.

Jammeh also cited external interference "the internal affairs of The Gambia and the unwarranted hostile atmosphere threatening the sovereignty, peace, security and stability of the country".

A former coup leader who has ruled the West African country since 1994, Jammeh initially conceded defeat  in the December 1 vote but a week later contested the poll's results stating irregularities.

Barrow, who is scheduled to take office on January 19, insists his inauguration will proceed as planned.

"This decision was taken by the national parliament that convened, it seems, secretly," Al Jazeera's Nicolas Haque, reporting from Dakar in neighbouring Senegal, said on Tuesday.

"What this means is that all land, sea and air borders will be shut down - Gambia, as of right now, is effectively on lockdown."

The announcement of the state of emergency came hours after Gambia's ministers for finance, foreign affairs, trade and the environment  resigned from Jammeh's government .