MEXICO CITY (AP) — Hundreds of farmers continued to hold a remote dam in northern Mexico Friday as President Andrés Manuel López Obrador tried to explain to the country why water must be released to the United States under an international treaty.

Concern was building that if the farmers refuse to budge, the National Guard would be sent in again and there could be violence. The farmers say they're worried about having enough water for their crops. When they took control of the dam Tuesday, they closed the valves that were releasing water from the reservoir.

Overnight, power to the La Boquilla dam site in Chihuahua was cut and there were reports that cell phone service there had also dropped, making activists suspect a move by authorities to evict them could be imminent.

López Obrador repeated Friday that he believes the protest is driven more by politics than water concerns. He said the farmers should be told, “There is no lack of water, they won’t run out of water, which is already 100 percent guaranteed for this cycle.”

He again expressed condolences for a woman killed Tuesday after National Guard troops had withdrawn from the dam following a clash with protesters. The National Guard has said four vehicles began following guardsmen who were transporting three detainees Tuesday night.

The National Guard said shots were fired from the vehicles and troops returned fire. A woman was killed and a man seriously wounded. The woman was buried Friday.

Mexico has fallen behind in the amount of water it must send north from its dams under a 1944 treaty, and time is running out to make up the shortfall by the Oct. 24 deadline.