BBC News with Jonathan Izard.

A spokesman for the Senegalese Army says its troops have entered the Gambia, where the long-time leader, Yahya Jammeh, is refusing to give up power. The new president, Adama Barrow, has been sworn in at the Gambian Embassy in Senegal. His inauguration sparked scenes of celebration in the Gambian capital, Banjul. The U.N. Security Council has unanimously backed the West African regional group, ECOWAS, which has threatened military intervention to force Mr. Jammeh out.

The U.S. Defense Secretary, Ashton Carter, says airstrikes against Islamic State fighters in Libya have killed more than 80 jihadists. The raids on Wednesday by long-range American bombers targeted two IS camps in a desert area, southwest of the coastal city of Sirte.

The Mayor of Tehran has said that more than 20 Iranian firefighters are now known to have been killed, when a high-rise building collapsed on them as they were fighting a major fire. The collapse of the 17-story Plasco building was broadcast live on television.

Rescuers say they've not given up hope of finding survivors from an avalanche that smashed into a hotel in central Italy. At least 3 people have been killed, and about 30 are missing. The hotel on Gran Sasso Mountain was struck on Wednesday after a series of earthquakes shook the region.

The Brazilian President has authorized troops to be sent into the northern city of Natal to prevent gun violence spreading beyond the state's largest prison, whether there've been further disturbances. Police have been unable to regain control of Alcazuz Jail, since a riot at the weekend left 26 prisoners dead. In the city, over 20 vehicles are said to have been set alight, and petrol bombs thrown.

Donald Trump's nominee to become treasury secretary, Steven Mnuchin, has been defending himself during confirmation hearings against allegations of profiteering and assisting tax avoidance. Mr. Mnuchin's OneWest Bank foreclosed on loans to tens of thousands of home-owners following the financial crash, policies that critics have cited as a prime example of the kind of Wall Street greed that Mr. Trump had campaigned against.

BBC World Service News.