Updated | Gambia's parliament extends defeated President's office by three months

Gambia's National Assembly has passed a resolution to allow President Yahya Jammeh, who lost an election in December, to stay in office for three more months from Wednesday when he was due to leave power.

According to Reuters news agency, the decision, announced on state television, will raise tension with leaders of the Economic Community Of West African States (ECOWAS) who have threatened sanctions or military force to make Jammeh hand over to opposition leader Adama Barrow, who won the December election.

The 15-nation bloc has also repeatedly urged Jammeh to respect the outcome of the vote and step aside, a call backed by the UN Security Council, African Union and others.

Jammeh, who has ruled Gambia for 22 years after seizing power in 1994 coup, initially acknowledged Barrow as the winner of the election, but later rejected the ballot count as flawed and lodged a complaint with the country's Supreme Court.

On Tuesday, Jammeh declared a state of emergency just two days before he was due to step down, saying it was to prevent a power vacuum while the supreme court rules on his petition challenging the election result.

In a national TV address, Jammeh said on Tuesday the measure was necessary because of "the unprecedented and extraordinary amount of foreign interference" in the presidential vote.

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

The state of emergency, which is supposed to last 90 days, bans "acts of disobedience" and "acts intended to disturb public order".

The National Assembly resolution almost certainly gives the government authority to prevent Barrow's inauguration.

Barrow, who is in Senegal, was examining the implications of the assembly's resolution and the state of emergency, given the constitutional requirement for a handover and the need to maintain peace, his spokesman Halifa Sallah said.

Jammeh’s government has gained a reputation among ordinary Gambians and human rights activists for torturing and killing opponents.

The state of emergency prompted British and Dutch travel agencies to evacuate thousands of tourists.

"The potential for military intervention and civil disturbance is high," the British foreign ministry said on its website, a warning echoed on social media by its Dutch counterpart, who both urged citizens to avoid all but essential travel.

British travel agency Thomas Cook said it had "implemented our contingency plans to bring all our UK customers home," and was trying to arrange evacuation of up to 3,500 tourists from Banjul airport as soon as possible.

"We will operate a programme of additional flights into Banjul airport over the next 48 hours," the company said in a statement, adding this included four extra flights on Wednesday.

The Dutch travel firm TUI Nederland said it would also repatriate "about 800" clients, according to AFP news agency.