Congress has passed legislation cracking down on animal fighting, sending President Bush a measure that would make it a felony to transport an animal across state lines for fighting.

Approval of the bill marked the culmination of a nearly six-year effort to limit dogfighting and cockfighting, centuries-old traditions that most lawmakers and animal rights advocates now label brutal.

The Senate passed the measure by voice vote Tuesday night, following House passage by a lopsided margin on March 26, clearing it for Bush's signature.

"Animal fighting is cruel," said Sen. Patrick Leahy, D-Vt., the Judiciary Committee chairman. "Those engaged in animal fighting ventures must know that this crime is serious and will be punished as a felony."

Critics say animal fighting — popular in rural areas and Latin American communities — can also spawn other criminal activity, such as illegal gambling, narcotics trafficking, public corruption, and gang activity.

Wayne Pacelle, president and CEO of the Humane Society of the United States, called the measure "a powerful law that will go a long way toward eradicating these sickening forms of animal cruelty."

The measure also outlaws commerce in cockfighting weapons — knifelike instruments that are attached to roosters' legs during fights. Transporting animals across state lines for fighting would be boosted from a misdemeanor to a felony.

Dogfighting is illegal in every state, and New Mexico last month became the 49th state to ban cockfighting, making Louisiana the only state where it's legal.