Nigerian police say they have located a camp where 19 national youth service recruits are being held by gunmen but cannot move in as they believe the place is mined with explosives.

Police Commissioner Audu Bosso said drones helped locate the camp where the prospective National Youth Service Corps (NYSC) members were taken after being abducted last week in the south-eastern Imo state.

The exact location of the camp has not been disclosed and police have not identified those responsible for the kidnapping.

Omotosho Adewale, whose child is among those abducted, told the BBC that the kidnappers had demanded a ransom of 50m naira ($37,680; £28,440), which he could not afford.

"There's no peace of mind. I've not eaten in three days," he said in between tears.

Adewale appealed to the government for help.

Those kidnapped had been travelling from Ibadan in the south-west to NYSC orientation camps in Abia and Akwa Ibom states on Thursday when gunmen attacked their buses near Umunoha in Imo state.

The NYSC is a compulsory one-year programme for most Nigerian university and polytechnic graduates. Participants, known as corps members, are posted to different parts of the country to work and take part in community service, as well as to foster a sense of national unity.

Speaking to journalists, Bosso said they had tracked the kidnappers.

"The drone actually showed us exactly their location. But our predicament is that with the intel we have… the camp is mined with IEDs [homemade bombs]," he said.

Bulldozers and armoured vehicles are being deployed as police prepare for a rescue operation.

Kidnapping for ransom is a major security problem in Nigeria, involving both criminal gangs and armed groups.

The abduction in Imo state has caused widespread concern, with mass kidnappings less common in southern Nigeria than in some parts of the north.

Paying ransoms is illegal and authorities have repeatedly warned families against doing so, but relatives of kidnapped people are often under pressure to do so to secure their release.

The latest abduction highlights the risks faced by young people travelling across Nigeria to do their national youth service and has renewed calls for reforms.

The NYSC has previously said it would not deploy members to areas considered high-risk because of violence or the threat of abduction. Most parts of south-eastern Nigeria have not previously been classified as high-risk areas.

In the south-east, some previous abductions have been linked to separatist groups, including the Indigenous People of Biafra (Ipob).

Authorities have not linked the current abduction to any group.

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