A riot has broken out at a Victorian detention centre amid reports a group of youths has escaped the facility and carjacked motorists.
Police were called to the "riot and escape" at Malmsbury Youth Detention Centre around 2.50pm today.
At least seven inmates are still on the run in two hijacked cars.
A police car was reportedly rammed during the escape. Seven News has reported the escapees are driving "out of control" at high speed and have smashed into a civilian car on the Calder Freeway. One of the pursuits had to be abandoned by police after an escapee started driving in the wrong direction on the freeway. A local petrol station staffer reported a "petrol drive off", just before 4pm. Police reportedly lost track of the two hijacked cars a short time ago.
Thirteen inmates initially escaped the facility but six have since been caught. Five inmates who climbed on the centre's roof have came down around 4pm and are now in police custody.