CHICAGO (Reuters) - U.S. Transportation Secretary Pete Buttigieg on Tuesday announced a partnership with state attorneys general to fast-track investigations into complaints against airlines and ticket agents as part of the Biden administration's efforts to enhance consumer protections.

Currently, the authority to enforce passenger protections lies solely with the federal government. And while state attorneys general receive consumer complaints, airlines are not legally required to respond to their inquiries.

Under the partnership, Buttigieg said the states will investigate complaints against airlines and refer them to the U.S. Department of Transportation for priority review and enforcement action.

They will also report carriers for failure to respond to requests for information. The DOT will give the states access to its consumer complaint database.

"The truth is we need force multipliers to help meet the need given the record-breaking air travel that we have seen," Buttigieg told reporters.

Complaints about U.S. airlines climbed sharply last year even as flight cancellations dropped to a 10-year low, data from the Transportation Department shows.

The Biden administration has been aggressively pushing measures to expand consumer rights for airline passengers.

It has proposed rules to make passenger compensation and amenities mandatory when airlines are responsible for flight delays or cancellations. It has also pressed carriers to get rid of junk fees, including those for seating families together.

Buttigieg has opened numerous investigations and imposed fines for carrier misbehavior. Last year, the DOT imposed a $140 million fine on Southwest Airlines for a December 2022 holiday meltdown that led to 16,900 flight cancellations and stranded 2 million passengers.

The latest move comes as passenger traffic in the United States is projected to reach an all-time high this year.

Buttigieg said the bipartisan agreement brings together attorneys general from Republican and Democratic states.

It includes 18 states such as California, New York, Nevada and Colorado that have some of the busiest U.S. airports. The DOT said seven more states - Delaware, Massachusetts, Minnesota, Oregon, Tennessee, Vermont, and Washington - are interested in joining the initiative.