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DALLAS (AP) — Intruders got over the fencing that protects Texas’ two busiest airports more than authorities disclosed, though there were no breaches last year.

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An Associated Press investigation shows 16 breaches of perimeter security at Dallas-Fort Worth International or George Bush Intercontinental since 2004.

The airports acknowledged 13 incidents when AP revealed problems with airport defenses last year.

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Federal records showed three more breaches than DFW told AP about. Among them: A 2012 case in which a man squeezed through a perimeter gate and was stopped near a runway.

The airport did not explain the discrepancy.

Airports say their perimeters are strong and note no breach involved a known terrorist plot. Nationally, breaches are happening about every 10 days at one of the 31 major airports AP studied.

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