Nine people were detained and one was missing after trying to walk across the Canada-United States border in the early hours of Tuesday morning, a Minnesota sheriff says.

The group made their illicit crossing in woods near Sprague in southeastern Manitoba and called 911 at approximately 4 a.m. as they were suffering from hypothermia, Steve Gust, the sheriff of Roseau County, said Tuesday. 

"Some were transferred to hospital but the majority of them were pretty good," Gust said. "They were wet and had frozen clothing."

There is an official port of entry on a highway that runs through Sprague and across the border into Warroad, Minn., but Gust said the group was away from that port of entry.

U.S. customs officials said the group was located in a flooded bog west of Warroad. The area includes a large state forest that runs up to the border.

"Border patrol agents provided immediate care as medical first responders and contacted local emergency medical services and local law enforcement agencies for additional assistance as needed," read a written statement from the U.S. Customs and Border Protection agency.

"Agents were able to determine seven out of the nine people in the group had illegally entered the United States and did not have any documentation allowing them to be legally present in the United States."

Manitoba RCMP had people in the area, including a search and rescue team looking for the reported missing person.

Last year, a family of four from India froze to death while trying to walk across the border further west, near Emerson, Man.

The frozen bodies of Jagdish Patel, 39; his wife Vaishaliben Patel, 37; their 11-year-old daughter, Vihangi; and their three-year-old son, Dharmik, were found on Jan. 19, 2022, just metres from the U.S. border.

Steve Shand, a Florida resident, was charged with human smuggling.

U.S. Customs and Border Protection has reported a growing number of people trying to enter North Dakota, Minnesota and Wisconsin illegally from Canada since last fall.