The UK is sending 750 military personnel to Sierra Leone to help deal with the deadly Ebola outbreak, the Ministry of Defence has said.
They will help build a treatment facility in the West African country.
The BBC understands the UK will also send the Royal Fleet Auxiliary ship Argus and three Merlin helicopters.
More than 3,400 people have died during the current Ebola outbreak, nearly all of them in West Africa. In Sierra Leone the death toll is at least 678.
Save the Children has reported the rate of infection is increasing in Sierra Leone, with five new cases every hour.
There is no cure or vaccine for Ebola – one of the world’s deadliest viruses.
It follows an earlier confirmation from the MoD that 40 soldiers based in Northern Ireland have been deployed to Sierra Leone.
The Royal Scots Borders 1st Battalion is based at Palace Barracks in Holywood, Co Down.
It is not clear whether the 40 are included in the total of 750.
The deployment of UK troops comes as further details are released about the case of a Spanish nurse infected with Ebola – the first person known to have contracted the virus outside West Africa.
A doctor in Madrid has said Teresa Romero remembers touching her face with her gloves after treating a dying priest.
A World Health Organization adviser earlier warned that more cases could be expected among medical staff, even in developed countries.