Mexico said it opposes the decision of the U.S. Section of the International Boundary and Water Commission (IBWC) that it will not object plans to build a border fence in floodplain areas in South Texas, according to and The Associated Press and the local newspaper The Rio Grande Guardian.

The decision by the U.S. IBWC comes despite objections from its Mexican counterpart. Mexico argues the fence would deflect floodwaters to its side of the Rio Grande and violate a bi-national treaty.

Rodolfo Montero, Rio Grande Valley area operations manager for the IBWC, spoke about his agency’s decision at a meeting of the IBWC’s Lower Rio Grande Citizens Forum in Mercedes on Wednesday afternoon. He said the U.S. would not be breaking any international treaties if it went ahead with federal plans and built permeable border walls in the floodplains of Los Ebanos, Rio Grande City and Roma over objections from Mexico.

Jesus Luevano, secretary of the commission’s Mexican section, said in an email Tuesday that Mexico’s position is that the “wall constitutes an obstruction of the normal current … in terms of the 1970 Boundary Treaty, therefore we continue fighting its placement with respect to the Rio Grande flood zone.”