Six women have been taken into custody after chaining themselves to the door of TD Bank branch near City Hall to protest the North Dakota oil pipeline project, police said.

Police said the women used PVC pipes to lock the doors of the bank at 15th Street and JFK Boulevard. A specially trained team from the police department had to use grinders to remove the metal chains, police said.

The protesters were taken to Central Detectives. No word yet on charges.

Bank employees hit the robbery alarm button about 7:45 a.m. to alert police, officials said.

"They chained themselves to the door," said Police Capt. Jack Ryan.

TD Bank has been the object of a number of protests across the country. The bank along with a number of other banks has invested in the project near the  Standing Rock Sioux Reservation.