Kidnappings in Nigeria
Alfred Nelson-Williams, Sierra Leone's deputy high commissioner, kidnapped
Incident marks first kidnapping of S Leonean diplomat in over 50 years
Hundreds of schoolgirls kidnapped by Boko Haram in 2014 still missing
Sierra Leone's deputy high commissioner has been abducted in Nigeria in the northern state of Kaduna, security sources and an official have said.
Government sources said on Friday that Alfred Nelson-Williams was taken as he was travelling by road from the Nigerian capital of Abuja to attend a ceremony in Kaduna, a city some 200km north.
Local security officials said they were still investigating how the kidnapping took place.
"We want to establish whether he had security escorts with him and what happened to them," Yusuf Yakubu Soja, Kaduna state security official, told the AFP news agency.
"He was kidnapped on his way to Kaduna from Abuja to attend the passing out ceremony of military officers at the Armed Forces Command and Staff College in Jaji outside Kaduna."
Mohamed Bangura, Sierra Leone's information minister, said the government was working with Nigerian authorities to secure Nelson-Williams' release.
Neither he, nor police, confirmed whether the kidnappers had demanded a ransom.
An investigator from Nigeria's Department of State Security also confirmed the abduction, but did not disclose when the kidnapping took place.
"We are in touch with the kidnappers. They made some demands and we are trying to see how we can meet it and secure his freedom," the DSS investigator, who wanted to remain anonymous, told the Reuters news agency.
Foreign ministry sources in Freetown told AFP that "this is the first time that a Sierra Leone diplomat has been kidnapped anywhere on posting since independence in 1961".
Kidnappings for ransom are a common problem in parts of Nigeria.
This week, two Indian workers were kidnapped on their way to work in central Benue state. The pair have yet to be released.
Last week, three Australians, a New Zealander and a South African were kidnapped along with two Nigerians near the capital of Cross River state in the country's south.
READ MORE: Nigerian girls kidnapped by Boko Haram seen in video
They were released four days later, but officials did not disclose whether the kidnappers received any ransom.
In April 2014, 276 schoolgirls were kidnapped from their classroom in the remote northeastern town of Chibok by Boko Haram fighters.
The government of former president Goodluck Jonathan was criticised for its slow response to acknowledge the kidnapping and for its inability to find and recover the girls.