SAN ANTONIO -

Investigators are working to determine the cause of a late night fire that damaged two apartment units.

The blaze broke out Saturday at 10 p.m. at the Heather apartments in the 3600 block of Hidden Drive, just north of Loop 410 and Starcrest.

Investigators said the fire started in a unit on the first floor of the complex and spread to an apartment on the second floor.

Both those apartments were damaged.

All residents were able to get out OK and no one was hurt.

The cause of the fire is unknown.