The U.N. refugee agency is condemning the kidnapping of several Congolese refugees by the Lord's Resistance Army rebel group.

The U.N. High Commissioner for Refugees said Friday that LRA fighters kidnapped 16 people last weekend who had been working in their fields in Congo, just over the border from Central African Republic. The rebels released 13 of them but are still holding three refugee boys.

The agency says the LRA, which has terrorized parts of central Africa for more than 25 years, has stepped up its attacks since the arrest of a top commander earlier this year.

The commander, Dominic Ongwen, faces charges of war crimes and crimes against humanity at the International Criminal Court.