A plane carrying four UN officials made an emergency landing in Bolivia's northern La Paz department, and all on board are safe, a local government official said Friday.

Local residents found the Cessna light plane of the Bolivian Air Force in a sports field, said Vidal Machicado, mayor of Asunta city in La Paz department.

"The people aboard are all in good condition," he said, referring to the UN officals and two crew members. However, he did not say what caused the emergency landing.

The plane, which took off at around 9:30 a.m. local time (1330 GMT) Thursday from El Alto airport, went missing while monitoring coca fields.