Mexican authorities said Thursday that they had rescued 165 migrants, including seven children, after a raid by soldiers on a safe house near the U.S. border.

The U.S.-bound migrants, mostly Central Americans, had been held at gunpoint for two to three weeks, crammed inside a filthy home not far from the U.S. border city of McAllen, Tex., according to Mexico’s Interior Secretary.

While it is not unusual for Mexican police and soldiers to announce similar raids on safe houses run by smugglers and trafficking organizations, the number of migrants found during Tuesday’s bust is among the largest in memory.

It is also not uncommon for migrants who have hired smuggling guides to tell authorities that they were kidnapped, rather than admit to paying for the illegal trip to the United States.

But Mexican officials said that the 165 were being held against their will and that they had been systematically handed over to the kidnappers while trying to sneak across the border.

Interior Secretary spokesman Eduardo Sanchez said soldiers responding to a tip Tuesday in the municipality of Diaz Ordaz spotted an armed man standing guard outside the dwelling with a rifle. He was the only suspect arrested.

Inside the house, 165 people were being held in “precarious, unhealthy conditions,” Sanchez said.

The dominant drug-trafficking organization in the area, Los Zetas, is notorious for kidnapping migrants and exacting ransom payments from their relatives in the United States or their home countries.

One Zeta kidnapping gang massacred 72 migrants at an isolated ranch in August 2010 in the same state, Tamaulipas, where Tuesday’s bust occurred.

The 165 migrants included 77 from El Salvador, 50 from Guatemala, 23 from Honduras, 14 Mexicans and a man from India, authorities said.