New York  - Humanitarian workers and United Nations personnel on diplomatic missions have become prime targets for kidnapping, UN Secretary General Ban Ki-moon said Wednesday on the International Day of Solidarity with Detained and Missing Staff Members.

Nineteen UN staff members have been arrested, detained or are missing, Ban said, urging governments and non-government organizations to help locate and free them.

"Anyone serving the United Nations, supporting us as a partner or reporting on our work is a potential victim, as recent high-profile hostage cases in Niger and Pakistan attest," he said.

John Solecki, an American who headed the UN refugee programme in Pakistan, was abducted in February, while two Canadian diplomats on mission in Niger were kidnapped last December.

Ban said he has been discussing the cases of missing UN staff with government leaders in South Asia and Africa, seeking their help for the release of the detainees.

"I also wish to stress how painful it is to see the impunity enjoyed by those who target the UN and our partners," he said. "The perpetrators must be brought to justice."

The Canadian diplomats, Ambassador Robert Fowler and his aide Louis Guay, are believed to be detained in Niger. Last week, the captors set free Soumana Mounkaila, a driver who was with them in a UN-marked vehicle.

Fowler was on an official UN mission, trying to find ways to settle a growing conflict led by Tuareg nomads against governments in Niger and Mali. (dpa)