CHICAGO (CBSNewYork/AP) — United Airlines chief executive officer Jeff Smisek has stepped down as chief executive officer, chairman and president effective immediately, the airline said Tuesday.

Smisek’s departure is connected with an investigation into dealings with the Port Authority of New York and New Jersey.

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The Chicago-based airline has named Oscar Munoz as president and chief executive officer. Munoz will continue to serve on the board.

United also said Tuesday its executive vice president of communications and government affairs and its senior vice president of corporate and government affairs have both stepped down.

United disclosed earlier this year that the company and some of its executives had received subpoenas from a federal grand jury for information about dealings with the Port Authority of New York and New Jersey. United said it was conducting its own internal investigation.

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Former Port Authority chairman David Samson’s activities have been subject of document requests from the U.S. attorney’s office in New Jersey, including Samson’s votes on United Airlines projects at Newark Airport at the same time United was restarting flights from Newark to Columbia, South Carolina, near where Samson has a vacation home.

The investigations are ongoing and the company continues to cooperate with the government.

Port Authority spokesman Steve Coleman declined to comment late Tuesday.

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