The number of confirmed cases of coronavirus in Nigeria has risen to 40.
This is after four more people tested positive, three in Lagos and one in the capital, Abuja.
The National Centre for Disease Control said two of the latest cases involved people who had recently travelled from abroad.
On Monday night, a ban on all international flights kicked in and Nigeria closed its land borders to try and slow the spread of the virus.
Civil servants in the cities of Abuja and Lagos have been instructed to work from home.