The United Nations is protesting Eritrea's arrest of a U.N. staff member, who is accused of human smuggling.

The U.N. mission watching the border between Eritrea and Ethiopia said Friday it is working to secure the release of an employee who was arrested earlier this week while driving an official vehicle.

Eritrea's Information Ministry says police detained U.N. staffers on Monday for allegedly attempting to smuggle young people and property out of the country.

The ministry's statement refers to multiple staff members without specifying how many people were arrested.  The U.N. mission says only one man was arrested.  The mission says a full investigation is under way.

U.N. forces are overseeing the implementation of a ceasefire agreement signed in 2000 by Eritrea and Ethiopia.  The neighboring countries were engaged in a two-year border war that killed about 70,000 people.