A new regulation, approved by the federal government Wednesday, has mandated that dogs will now be the only type of service animal allowed on all U.S. flights.

The new rule is meant to allow airlines to bar other types of animals from being brought on flights tagged as emotional support pets.

The rule was initially proposed by the Department of Transportation earlier in the year. Since then, it has sparked a debate between airlines, passenger rights groups and advocates for people that rely on animals for emotional support.

Before the passing of the new rules, passengers were allowed to bring animals on flights if they were able to prove that they were necessary for emotional support or as service animals.

Transport regulators previously told airlines that service animals such as cats and dogs should be allowed. However, some passengers had brought a wide variety of animal species on flights, which they claimed to be service animals. This included monkeys, rabbits, birds and even miniature horses.

According to the transport regulator, the continued bringing of "unusual species" onboard U.S. flights has "eroded the public trust in legitimate service animals" with some passengers abusing airline policies. The regulator said that cases of "fraudulent representation" of service animals have been increasing, which is why it had chosen to act accordingly.

Airlines of America, a group that includes all of the major U.S. carriers, welcomed the new rules and stated that it should be advantageous to all people involved.

"The Department of Transportation's final rule will protect the traveling public and airline crew members from untrained animals in the cabin, as well as improve air travel accessibility for passengers with disabilities that travel with trained service dogs," the group's president Nicholas Calio said in a statement.

The Association of Flight Attendants also welcomed the news stating that the industry sorely needed the federal government to step in. The trade union said that the bringing of untrained animals by passengers has repeatedly threatened the safety and health of travelers and crew members on dozens of flights.

Groups advocating for people that rely on service animals for physical and psychiatric support disagreed with the new rules, stating that they were too rigid and that it did not take into account travelers with special needs.