Nigeria will only allow cargo vessels that have been at sea for more than two weeks to dock in its ports to prevent the spread of coronavirus, President Muhammadu Buhari said on Thursday.
Health experts fear a widespread outbreak in Africa's most populous country of 200 million people which could overwhelm its creaking healthcare system.
Nigeria has closed its land borders and international airports in the last week to curb the spread of the virus.
Buhari said on Twitter he had issued a directive that "only cargo vessels that have been at sea for more than 14 days be allowed to dock in our ports, after the crew have been tested and confirmed disease-free by the port health authorities".
Earlier, the Nigeria Center for Disease Control (NCDC) said 14 new coronavirus cases had been identified, taking the total number to 65. Six of the new cases were detected on one vessel.
The president said the new restrictions would not apply to ships carrying oil and gas products because there was minimal human contact on such vessels.
The restrictions risk creating supply chain problems.
Manufacturers said this week the port wait time for ships had jumped to as long as 90 days. With airports closed to international flights and limiting crew access, air cargo deliveries could become increasingly unreliable.
(Reporting by Alexis Akwagyiram; Additonal reporting by Libby George; editing by Ed Osmond)