SUNOL -- Firefighters were able to contain the spread of a vegetation fire to 20 acres Wednesday evening, according to the Alameda County Fire Department.

Crews responded around 5:33 p.m. along Vallecitos Road, said department spokeswoman Aisha Knowles. Crews quickly requested that the California Highway Patrol shut down the road in both directions while firefighters from Alameda County, the Livermore Pleasanton Fire Department and CalFire worked to contain the blaze.

The road has since been reopened.

The fire was contained within the hour, and no injuries were reported.

The cause of the fire is under investigation.

Check back for updates.

Contact Katie Nelson at knelson@bayareanewsgroup.com and follow her at Twitter.com/katienelson210.