Image copyright AP Image caption Seventeen teenagers were still at large on Tuesday morning

Nine teenagers are still being sought after more than 30 held at a juvenile detention centre in Tennessee escaped by crawling through a fence.

They escaped late Monday evening from the Woodland Hills Youth Development Center in Nashville.

Police said some escapees had handed themselves in, some were brought back by parents and some were picked up.

The centre holds juvenile prisoners, many of whom have committed at least three felonies, a state spokesman said.

The teenagers who escaped ranged in ages from 14 to 19, said Rob Johnson of the Tennessee Department of Children's Services.

The escape occurred when a large group of teenagers went outside all at once after a guard shift change, Mr Johnson said.

Officials did not know if it was planned or spontaneous.