Police have arrested several South Americans after a seizure of cocaine
Sierra Leone's President Ernest Bai Koroma has said he will prevent the country becoming a key transit point for the international drugs trade.
His comments follow the seizure by police of a plane loaded with cocaine at an airport outside the capital.
The plane, which was abandoned on the runway, was carrying a 600kg cargo, worth an estimated $54m.
Latin American drugs cartels are using West Africa as a transit point to smuggle cocaine to Europe, the UN says.
Fifty-eight people are being held over the seizure of the plane, the BBC's Umaru Fofana reports from the capital, Freetown.
Sierra Leone has a weak law on narcotics that has seen traffickers pleading guilty and walking free after paying a fine, he says.
But with help from the UN, the cabinet has approved tougher laws on narcotics that are expected to be taken to parliament this week.
'No sacred cows'
"I would like to assure the general public and the international community that on no account will our country be used either as a direct transit point or a final destination for the international trade of narcotics," the president said in a radio address to the nation.
"I want to assure you all that there will be no sacred cows in the treatment of suspects."
The president also said he had sought technical help from Britain for investigation.
After years of war, Sierra Leone is one of the world's poorest countries and corruption is a major problem.
Guinea-Bissau, another weak West African state, has also been targeted by Latin American drugs cartels.
Following the seizure of the plane a week ago, Sierra Leone police arrested seven foreign nationals - three Colombians, two Mexicans, a Venezuelan national and a US citizen - in a car 10km (six miles) from Freetown's Lungi international airport.
An eighth foreigner was reportedly arrested on Monday.
The small aircraft had arrived without authorisation, carrying a fake Red Cross emblem, police said.