Members of the International Longshoreman's Association walked off the job at the Port of Newark and Port of Elizabeth Friday morning — but the reason wasn't clear .

The Port Authority of New York and New Jersey issued an alert about a work stoppage on Friday morning at ports in both states and warned that no new trucks would be allowed entrance into the port.

“As the agency that oversees the largest port complex on the East Coast, we strongly urge the ILA members to return to work immediately and resolve their differences after they return," the Port Authority wrote in a statement Friday afternoon. "In the meantime, Port Authority Police are actively working to ensure public safety for all of the stakeholders at the port.”

The trucking industry news website reported the reason for the action may be a protest of hiring rules imposed buy the Waterfront Commission of New York Harbor, which oversees port hiring.  ILA spokesman Jim McNamara told New Jersey 101.5 he was not aware of the job action.

Edison Villacis, president of the Port Drivers Association. said "No one knows the real issue but were told by the ILA to walk out" and urged everyone to stay away and not add to the congestion at the yard.

The Port of New York and New Jersey is the largest on the east coast and the third-largest in the nation, according to the Port Authority.

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