Nov. 6 (UPI) -- A reduction in flights will affect 40 airports amid the federal government shutdown, which has put a strain on air traffic control staffing, unnamed sources said Thursday.

The Federal Aviation Administration hasn't listed the airports, but sources released the tentative list to ABC News, CBS News and The Washington Post.

Most of the airports affected are in major cities, such as New York, Chicago, Houston and Los Angeles. But other, less-busy airports are also on the list, such as Tampa Bay, Fla.; Anchorage, Alaska; and San Diego.

Transportation Secretary Sean Duffy announced the 10% flight reduction on Wednesday, and said the cuts will begin on Friday.

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