New York – Port Authority police are on high alert today following what the agency believes is a “credible threat” to its bridges and tunnels, The Post has learned.

A source said the information that led to the alert came from a prisoner in Afghanistan.

A secret briefing was held yesterday for PA emergency-service cops to detail the threats, which may involve trucks carrying gasoline.

Additional officers will be patrolling the crossings.

The last time the PA force was put on a similar alert was in September, when authorities tracked Afghanistan native Najibullah Zazi from New York to his Colorado home and arrested him there.

Zazi pleaded guilty in February to terrorism charges in a plot to detonate homemade bombs in the subways.

(Source: NY Post)