McLEAN, Va. -- Tour buses carrying Woodland Hills West Junior High School students were involved in a collision on the George Washington Memorial Parkway early Friday evening.

The two buses were carrying eighth-graders on their way to Washington as part of an annual field trip when the crash happened at about 5:30 p.m.

A representative for the Woodland Hills School District said there were 75 students on the Trailways buses who were traveling southbound on the parkway during rush hour.

Twelve students were injured, officials said, and seven were taken to local hospitals. Officials said none of the injuries was life-threatening, and they said they believe all of the students rejoined the field trip.

One of the Trailways buses stopped, and the other rammed into the back of the first, officials said.

The students were offloaded onto other buses and continued their trip into the nation's capital, officials said.

The southbound lanes of the parkway, a main artery into and out of Washington, were tied up for about three hours before reopening.