Providence, R.I. ? The mayor of Providence wants to slap a $150-per-semester tax on the 25,000 full-time students at Brown University and three other private colleges in the city, saying they use resources and should help ease the burden on struggling taxpayers.

Mayor David Cicilline said the fee would raise between $6 million and $8 million a year for the city, which is facing a $17 million deficit.

If enacted, it would apparently be the first time a U.S. city has directly taxed students just for being enrolled.

The proposal is still in its early stages. But it has riled some students, who say it would unfairly saddle them with the city’s financial woes and overlook their volunteer work and other contributions, including money spent in restaurants, bars and stores.

“We want to support the city as best we can, but financially is not really what we can afford to give,” said Heather Lee, president of the Brown Graduate Student Council. “We’re more able to provide labor, we’re more able to apply the things that we’re learning in the classroom, than we are to write a $300 check.”

Cities often look for revenue from universities to compensate for their tax-exempt status, and many schools already make voluntary payments to local governments. Providence’s four private schools — Brown, Providence College, Johnson & Wales University and the Rhode Island School of Design — agreed in 2003 to pay the city nearly $50 million over 20 years.

The idea of a student head tax has been floated before in other cities, generally to start discussions about collecting money from universities in lieu of taxes.

Cicilline’s office said there is no study showing how much students cost Providence for the use of police and fire protection and other services.