Pamela Burns, president and chief executive officer of the Hawaiian Humane Society, praised the new law and said it may be a deterrent to Hawai'i cockfighters who export and import birds and equipment.

"Cockfighting is still a misdemeanor here," Burns said, "but there is a business of shipping birds out of Hawai'i (to the Mainland and foreign countries). It puts them on alert that it's a federal felony offense now."

Burns said the reason most commonly given for shipping birds out of state is "rooster shows."

State lawmakers passed an animal-cruelty bill this year, but it did not cover cockfighting.

In Washington, D.C., the Senate adopted the federal measure last month, after it was approved by the House.

"With this law, we can clamp down on these cruel, inhumane practices," said U.S. Sen. Maria Cantwell, D-Wash., the bill's chief Senate sponsor.

Dog fighting is banned throughout the U.S. and is a felony in 48 states. Cockfighting is a felony in 33 states and legal only in Louisiana.

Many laws against animal fighting carry a punishment of no more than a year in jail.

Animal-welfare groups had long urged Congress to adopt stronger penalties on blood sports such as dog fighting and cockfighting.

"Animal fighting is a barbaric and inhumane practice, and it is fitting and appropriate that we now have a national policy condemning and criminalizing this form of organized animal cruelty," said Wayne Pacelle, president and CEO of The Humane Society of the United States, which led the push for stronger penalties against animal fighting.

The new law should substantially curb the transport of fighting animals across state and U.S. borders, Pacelle said.

The Humane Society is already seeing some major breeders of fighting roosters cut back on production, he said.

The bill is H.R. 137.