U.S. Border Patrol agents arrested 11 men and five women in a series of encounters at the start of this month near the border between North Dakota and Canada.

The arrests are the latest in a surge of illegal crossings at the northern border, according to data from U.S. Customs and Border Protection.

“These cases demonstrate a great collaboration between Border Patrol Agents and our local law enforcement partners,” Chief Patrol Agent Scott D. Garrett said in a news release on Friday.

On July 1, a camera sensor alerted authorities to a man walking toward the Canadian border at the Metigoshe State Park, according to an affidavit recently unsealed by the U.S. Attorney’s Office.

Agents later stopped the same man driving a car carrying four others from Mexico. Investigators say all of them admitted to entering the U.S. illegally.

“Several individuals admitted to having flown into Canada on a tourist visa and admitted to having crossed the Canadian Border near a lake and campground,” Agent Kevin Backes wrote in his affidavit.

One of the passengers in the car also said she paid $3,400 “to be smuggled into the United States,” according to the affidavit.

On July 4, agents arrested six more people from Mexico after authorities stopped a truck near Kenmare, ND.

“The occupants of the vehicle all knew each other from work and were traveling to Chicago, Illinois, to work in road construction,” one of the men told an agent. “He stated that the vehicle belonged to his boss, ‘Jimmy,’ and that Jimmy had told him to cross the border to meet them in Chicago.”

On July 8, agents made arrests in a third case near Bottineau, ND.

Prosecutors accuse a man and a woman with U.S. citizenship of trying to smuggle three others, including at least one family member, who are originally from Poland.

The U.S. Attorney’s Office in Fargo declined to comment, citing an ongoing investigation.

Federal data shows agents have already made more than 12,000 “encounters” with people suspected of crossing the northern border illegally since October of last year.

That figure is already 2,000 encounters more than the entire previous fiscal year.