MONTGOMERY CO., Va. -

UPDATE: The wreck has cleared.

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A wreck is causing delays on Interstate 81 in Montgomery County on Monday morning.

As of 9:50 a.m., there is a four-mile backup around mile marker 126. That's two miles south of the North Fork Road exit.

The northbound left lane and both shoulders are closed.

The wreck happened around 7:30 a.m.

Check back for updates.