An industry trade group and a small, Texas-based Internet provider are among the first to mount a legal challenge to the federal government's new net neutrality rules.

On Monday, USTelecom — a group that includes some of the nation's largest Internet providers — filed suit in Washington, while Alamo Broadband sued the Federal Communications Commission in New Orleans.

The court filings kick-start a legal effort to overturn the FCC's regulations, passed in February, that aim to keep Internet providers from speeding up, slowing down or blocking Web traffic.

"We do not believe the Federal Communications Commission’s move to utility-style regulation invoking Title II authority is legally sustainable," USTelecom President Walter McCormick said in a statement. "Therefore, we are filing a petition to protect our procedural rights in challenging the recently adopted open Internet order.”

In its petition, Alamo alleges that the FCC's net neutrality rules apply onerous requirements on it under Title II of the Communications Act, the same law that the FCC uses to monitor legacy phone service.

"Alamo is thus aggrieved by the order and possesses standing to challenge it," the company's lawyers wrote in the petition, a copy of which was obtained by The Washington Post.

The challenges are coming much sooner than expected. Many analysts believed that Internet providers would have to wait until the FCC's rules were officially published in the Federal Register before being eligible to appeal.

But according to legal experts familiar with the challenges, certain sections of the FCC's rules operate on a different timeline. Those parts, referred to as the "declaratory ruling" sections of the net neutrality rules, were considered final as soon as the FCC published them on its Web site, according to the experts, which it did March 12.

"USTelecom is filing this protective petition for review out of an abundance of caution," USTelecom writes in its challenge, a copy of which was also obtained by The Post.

After the declaratory ruling becomes final, potential challengers have 10 days to file an appeal; both petitions were filed hours before the deadline.

In a statement, the FCC called the petitions "premature and subject to dismissal." It is unclear whether the FCC will be immediately asking for the cases to be thrown out.

Supporters of the FCC are eager for the battle to be joined.

"Our side does want an early challenge so that this administration will defend it, and [FCC Chairman Tom] Wheeler will defend it," said one industry lobbyist who represents smaller telecom firms. "The sooner the better."

Consumer advocacy groups that had pushed hard for the strong new rules said Title II was "the right law" and insisted that the FCC has a strong case.

"These companies have threatened all along to sue over the FCC's decision, even though that decision is supported by millions of people and absolutely essential for our economy," said Matt Wood, policy director at Free Press. "Apparently some of them couldn't wait to make good on that threat."

In a separate legal challenge filed Friday in Cincinnati, Tennessee sued the FCC over its February decision to block the state's restriction on city-run Internet service.

"The FCC has unlawfully inserted itself between the State of Tennessee and the State's own political subdivisions," the challenge alleges.