UPDATE 3 P.M.
St. Paul Fire Department provided an update saying there were a total of 51 passengers on a bus from Little Falls involved in the crash. Eight people were hospitalized with three of them in critical condition.
Both bus drivers were injured and needed to be extricated from their buses.
As of 3 p.m., MN-280 southbound remains closed, but tow trucks were on the scene working to clear the buses to re-open the highway to traffic.
UPDATE 1 P.M.
The crash on MN-280 happened after one of the tour buses involved took a sharp left from the on-ramp onto a grass embankment, before colliding with another bus on the main highway.
There were 43 people on the Andy's Charter Bus plus the driver, which collided with another tour bus on which they was only the driver.
Eight people were taken to a hospital after sustaining injuries, including both drivers. The Andy's bus was en route to the Minnesota State Fair.
At this stage, the State Patrol isn't sure what caused one of the buses to enter onto the grass bank.
MN-280 southbound is still closed at this stage. The State Patrol says it's hoping to re-open the road as soon as possible.
Minnesota 280 is closed southbound in Minneapolis after a collision involving two tour buses.
The crash happened north of Larpenteur Avenue, with the Minnesota Department of Transportation saying at 11:20 a.m. that the road is expected to be closed for at least three hours.
Traffic cameras show several emergency vehicles at the scene, including ambulances an fire engines.
Citing dispatch audio, the Star Tribune reported there are "multiple injuries" with two people said to be pinned.
Local hospitals have been warned to prepare for several victims arriving, the newspaper adds.
There are a large number of buses on city streets today because of the start of the Minnesota State Fair, though it's not clear if the vehicles involved were ferrying people to and from the nearby fairgrounds.