Washington ? From Ku Klux Klan members to Jewish militants, federal prosecutors have thwarted several would-be domestic terrorists in recent months, using FBI-led task forces whose primary duty is stopping al-Qaida and other international groups.

Since the attacks on Sept. 11, 2001, the FBI has doubled to 66 the number of joint terrorism task forces. Federal, state and local law enforcement agencies work closely together, sharing intelligence, informants and evidence — a far cry from the police turf battles of years past.

Preventing attacks by foreign organizations is the top priority of the task forces but they also work on homegrown cases.

Atty. Gen. John Ashcroft said the Justice Department was “committed to investigating, prosecuting, punishing, and most of all preventing, criminal acts of violence and vigilantism motivated by hate and intolerance.”

The FBI task forces have stopped a Pennsylvania KKK leader who allegedly sought to set off grenades at abortion clinics, and a militant Jew who wanted to bomb a Southern California mosque and the offices of Lebanese-American Rep. Darrell Issa, R-Calif.

The task forces helped send to prison a white supremacist who plotted to blow up black and Jewish landmarks in Boston and Washington. They were integral in the Jan. 8 arrest in Chicago of Matt Hale, leader of the white supremacist group World Church of the Creator, on charges of trying to have a federal judge killed.

In the Pennsylvania case, U.S. Atty. Mary Beth Buchanan said the arrest of David Wayne Hull of Amwell Township last week on weapons and explosives charges stemmed from cooperation between terrorist task forces in Pittsburgh and Philadelphia, ultimately involving officials in four states.

The government says Hull, 40, who calls himself the imperial wizard of the White Knights of the KKK, was testing bombs at his farm and tried to buy grenades to attack abortion clinics.

“Law enforcement agencies are reluctant to share information if they don’t know each other and trust each other,” Buchanan said. “It was through this information sharing that we were able to put the pieces together.”

Intelligence officials say al-Qaida remains the primary threat for another major attack on U.S. soil, but they point out that even a single individual can wreak mayhem.