HOUSTON (AP) - The Houston Zoo has suspended free admission on the first Tuesday afternoon of the month due to large crowds clogging traffic.

Zoo officials say about 12,000 people headed for the complex during a three-hour period on June 5. A statement Monday from the zoo says the traffic congestion created a potential hazard for emergency vehicles.

The cancellation means no free Tuesday afternoons on July 3 and Aug. 7.

Zoo officials say the free admission on the first Tuesday afternoon of the month will resume in September.

(Copyright 2012 The Associated Press. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.)