UPDATE (4:12 p.m.) Authorities were able to pinch the gas line late Friday afternoon, after a main line was ruptured in downtown Hamilton.

Officials said roads were reopened and all businesses but one were allowed to have workers returned.

Crews were still working to get the main line completely under control.

(3:00 p.m.) Construction crews hit a gas line in downtown Hamilton, forcing an evacuation of two downtown businesses.

Sergeant Bob Liercke with the Hamilton Police Department said the call came in at about 1:27 Friday afternoon.

"We have some construction on the 100-block of Fairgrounds Road that's been going on this week and today, the main gas line--it's a six-inch main just south of Fairgrounds Road --during construction got ruptured," Liercke said. "The gas is blowing straight into the air. At one point it was going 100 feet in the air. It was blowing primarily to the south. We haven't seen any significant wind changes, so it's blowing primarily into the south."

Fire officials confirmed they are evacuating an area around the fairgrounds.

"North of Fairgrounds we have B.J.'s and Ravalli Services evacuated," Liercke said. "South of Fairgrounds we have S&S Auto Body, McDonald's, Papa Murphy's, Evan's Ace, Fishhouse Tackle, Canyon View Dental,  the Bargain Corner Thrift Store, the Gold Coin Casino, and a UPS store all evacuated."

Liercke said Northwestern Energy was on scene within minutes of the main line rupturing.

No injuries have been reported.