An effort by Gov. Doug Ducey to use shipping containers to close a 1,000-foot gap in the U.S.-Mexico border wall near Yuma suffered a brief setback when two stacked containers somehow toppled over.

Claudia Ramos, a correspondent for the digital platform of Univision Noticias in Arizona, posted on her Twitter feed a photo she took August 15 of the containers on their side. She said they fell on the U.S. side of the border.

No witnesses have come forward to say what happened that night.

Ramos said contractors in the area told her that they believed the containers may have been toppled by strong monsoon winds.

But C.J. Karamargin, a Ducey spokesman, said that he doubted that hypothesis, adding that even though the containers are empty they still weigh thousands of pounds.

“It’s unlikely this was a weather event,” said Karamargin, suggesting that someone opposed to the wall was to blame.

The stacked pair of containers were righted by the morning of August 15.

“Clearly we struck a nerve. They don’t like what we are doing, and they want to keep the border open,” the spokesman said.

Officials with Ducey’s office say they were acting to stop migrants after repeated unfulfilled promises from the Biden administration to close the gap.

Federal officials have not commented on the state’s actions, which come without explicit permission on federal land. State contractors began moving and stacking 60-foot-long, 9-foot-tall shipping containers early August 12. Two other 1,000-foot gaps also will be closed off. The containers will be topped with 4 feet of razor wire.

Karamargin said that the Border Patrol informed the Governor’s Office around midnight that the containers were toppled.

“Those weren’t secured yet,” he said. “This happened before securing the containers to the ground. They will be bolted later and will be immovable.”