"It's a free-for-all down here," Minuteman President Chris Simcox said. "It's an amnesty rush."
He said his group rescued seven immigrants, found the body of another and led border agents to hundreds of immigrants on Saturday and Sunday.
U.S. Border Patrol agents confirmed the Minutemen were busy. One agent said in the first four hours of his shift Sunday morning, he had responded to calls involving as many as 60 illegal immigrants.
"The numbers may be going up because of the weather," Agent Robert Sanchez said. "We're talking about an area west of Nogales to Ajo ... That's a lot of ground."
For the month of April, armed Minuteman volunteers will be stationed at observation posts along smuggling corridors in Arizona, California, New Mexico and Texas in an effort to curb illegal immigration.
The Minuteman group is in its third year of border deployments. But this year, Border Patrol agents say the apprehension of illegal immigrants is sharply down.
"Whoever's saying that, they haven't been to Altar Valley," Simcox said.