TAPACHULA, Mexico (AP) — Mexico’s armed forces sent troops, vehicle convoys and helicopters into remote towns near the southern border with Guatemala on Wednesday after drug cartels blocked roads and cut off electricity in some areas over the weekend.

The drug cartels have taken control of so much territory in the rural southern state of Chiapas that some government workers had to be flown in by helicopter to repair power lines.

A combined force of about 800 soldiers, National Guard officers and police fanned out around the township of Frontera Comalapa, after videos surfaced over the weekend of a convoy of heavily-armed gunmen from the Sinaloa cartel rolling into one town, drawing cheers from some inhabitants. Church groups complained supplies were running out because of the gang roadblocks.

The government convoys Wednesday meet no armed resistance. But some locals are understandably skeptical about how long the peace will last.

The army carried out a similar operation in the area in May, but then withdrew.

Army Lt. Col. Felix Moreno Ibarra said Wednesday that this time, the soldiers will stay until control is regained over the area.

President Andrés Manuel López Obrador acknowledged Monday that the cartels have cut off electricity in some towns and forbidden government workers from coming in to the largely rural area to fix the power lines.

He said the cartels were fighting for control of the drug smuggling routes that lead into southern Mexico from Central America. But the area around the town of Frontera Comalapa is also a valuable route for smuggling immigrants, thousands of who have clambered aboard trains to reach the U.S. border.

The Sinaloa cartel is fighting the Jalisco New Generation cartel for control of the area, located in a rural, mountainous area north of the border city of Tapachula.

Four men, apparently members of the Jalisco cartel, were found dead over the weekend in a nearby town, according to an employee of the Chiapas state prosecutor’s office who spoke on condition of anonymity because the person was not authorized to be quoted by name.

The conflict threatened to spread over the border into Guatemala.

Col. Alex Manolo Tuyuc of the Guatemalan Army said about 2,000 soldiers and 350 vehicles had been sent to areas on the Guatemalan side of the border, after reports of Mexican cartel gunmen entering Guatemala.

“We got reports of armed men in vehicles crossing from Mexico into Guatemala and threatening communities” on the Guatemalan said, Tuyuc said.

In Chiapas, the local Roman Catholic Diocese said in a statement over the weekend that cartels were practicing forced recruitment among local residents, and had “taken over our territory,” blocking roads and causing shortages of basic goods.

López Obrador also appeared to lend credence Monday to the videos showing residents applauding about 20 pickup trucks full of armed Sinaloa cartel gunmen as they entered one Chiapas town. The president said the cartels might be forcing or bribing residents into acting as civilian supporters, known in Mexico as “social bases.”

“On the side of the highway there are people apparently welcoming them,” López Obrador said of the video, which shows uniformed men aboard the trucks brandishing rifles and machine guns mounted on turrets. Voices in the video can be heard shouting phrases like “Pure Sinaloa people!”

“These may be support bases, like those in some parts of the country, because they give them food packages, or out of fear, because they have threatened them,” the president said.

But López Obrador said the problem was a local, isolated issue that had been magnified and exploited by his political foes.