In a reproach to US foreign policy on Thursday, Spain's National Court Judge Baltasar Garzon told delegates at the United Nations that "terrorism is a crime... not a movement".
"The war ... is today distorting the effectiveness of the fight against terrorism," Garzon added. "The only way to combat terrorism in any of its manifestations is with the strength of law and reason and not the reason of force."
Washington has been accused of torture and abusing detainees in Iraq, Afghanistan and Guantanamo Bay in Cuba in a quest for intelligence in a war on terrorism rather than for evidence to prove crimes.
Garzon said such tactics meant going down a dangerous road as illegally obtained evidence could not be used in a court of law.
Without mentioning Washington by name, Garzon said Spain had recently received no response when it sought to extradite three Spaniards charged with crimes in Spain and being held at the US detention centre in Guantanamo.
"It is not because they don't want to cooperate, but the different point of view in the fight against terrorism from one area to the other produces a practical result such as this.
"The only way to combat terrorism in any of its manifestations is with the strength of law and reason and not the reason of force"
Spain's National Court judge
"Three people who are not charged in one country are not delivered to another country where they are sought so they can be brought to justice," he said.
Addressing the same UN session, Barry Sabin - chief of the US Department of Justice Counter-Terrorism Section - said Washington agreed the terrorist threat must be pursued through law enforcement, using only legal tactics and in close cooperation with other governments.
Garzon, who has been investigating Islamist extremists since 1991, is best known for a failed attempt to extradite former Chilean leader General Augusto Pinochet from Britain in 1998 and put him on trial in Spain for human rights abuses committed in Chile.
Britain put Pinochet under house arrest for two years while courts heard details of atrocities under his rule, prompting Chile to examine his legacy and hear human rights cases.
Garzon was also responsible for keeping Aljazeera correspondent Taysir Alluni locked up as he investigated alleged links with al-Qaida.
The Spanish judge determined there was sufficient evidence to hold the 57-year-old journalist further and suggested Alluni joined an Islamist group in 1995 that may have offered support to al-Qaida.
Last month, Alluni gave his testimony to the Spanish court, described how he had interviewed Osama bin Laden weeks after the 11 September 2001 attacks but denied any link to his network.