Kimberly Rivera. File image: Aaron Vincent Elkaim/The Canadian Press/AP Photo

A female U.S. Army deserter who in 2007 moved to Canada to avoid being sent back to Iraq was arrested Thursday. Authorities took her into custody at a border crossing in New York after the Canadian government ordered her deported.

Thirty-year-old Kimberly Rivera, an Army private and mother of four, had fled to Canada to escape returning to Iraq, where she had already served three months. She traveled to Canada during a home leave, citing her opposition to the war in Iraq.

Chief Tom Russert, Public Affairs Liaison for Customs and Border Protection field operations, confirmed Rivera's arrest Thursday morning at the Alexandria Bay Border Crossing.

"She was wanted for being a military deserter, there was a warrant for her arrest," said Russert. He said Rivera was arrested by U.S. Customs and Border Protection personnel and turned over to Fort Drum, an Army base 30 miles away from the border crossing where she was arrested.

Lt. Col. David Konop, a spokesman at Fort Drum, New York confirmed to ABC News that Rivera is at the base. He said "her case is being examined while her needs are being addressed."

He said she was at Fort Drum only because of its proximity to the border crossing where she was detained. He said it was unclear what her future movements might be.

Rivera applied for refugee status in Canada in 2007, but her application was denied. Her legal fight to remain in Canada culminated in a deportation order last month.

In a statement, the War Resisters Support Campaign, a Canadian group advocating for Rivera , said she had "voluntarily presented herself at the U.S. border this morning."

The group said, " Kimberly now awaits punishment for refusing to return to Iraq, a conflict which Kimberly and Canada determined was wrong."

The U.S. Army classifies deserters as those soldiers who have not reported for duty for more than 30 days. The Army could choose to prosecute her and potentially seek a court martial or choose the more common practice of an administrative separation.