As the United States moves beyond blocking funds of Usama bin Laden's network to include other terrorist groups, America's most important bloc of allies is being less aggressive.
The European Union has frozen assets of just two of 28 groups on a U.S. list of non-Al Qaeda organizations. Out of the dozens of individuals on Washington's list of suspected terrorists, the EU targeted eight.
U.S. targets left off Europe's list, published in December, includes the PKK Kurdish rebels threatening Turkey, the Shining Path group in Peru and the Revolutionary Armed Forces of Colombia.
In a 15-nation bloc that often doesn't see eye-to-eye with each other, some EU members cited a lack of evidence that groups were terrorists, legal concerns, and a hesitance to support governments with dubious human rights records, according to diplomats who spoke on condition of anonymity.
Europe has embraced other anti-terrorism measures with impressive speed since the Sept. 11 terror attacks. But their limited fund-blocking response underscores how hard it is for the United States to build consensus for cracking down on armed groups, terror experts say.
"As you expand and broaden the definition of terrorism, you are likely to also expand the likelihood of disagreement between countries over who should be included and how to deal with it," said Ivo Daalder, senior fellow at the Brookings Institution, the Washington-based think tank.
The Bush administration has welcomed the world's anti-terrorism cooperation since Sept. 11, noting that 149 countries had frozen more than $104 million in assets of groups and individuals that America has tied to terrorism.
But as the United States added non-Al Qaeda groups to its financial blacklist in the past six months, agreement from allies on concerted action was harder to come by.
"In those few cases where the United States has taken action and our friends and allies have not, we are working internationally on several fronts to encourage other blocking countries to take action as well," said Tasia Scolinos, spokeswoman for the U.S. Treasury's Office of Foreign Assets Control, the primary agency charged with freezing terrorist assets.
Despite 15 different legal systems and sets of traditions, the EU has made big strides since Sept. 11 to implement an EU-wide arrest warrant, craft a common definition of terrorism and mandate minimum penalties for those convicted of terrorist crimes.
And individual nations are free to act on their own. Britain went after assets of many more U.S.-listed non-Al Qaeda groups, including Japanese cult Aum Shinrikyo and IRA dissidents known as the Real IRA.
But such individual actions won't bring Europe-wide opinion closer to Washington's over who is a terrorist.
The differences were highlighted in December when President Bush froze the assets of Hamas and closed the offices of a Texas-based foundation that allegedly helped finance the militant Palestinian group.
The EU responded later that month, drawing a distinction between Hamas' military wing and its political leaders by blocking the funds of the Hamas "terrorist wing." The EU went after the Palestinian Islamic Jihad but did not include Hezbollah on its list, although it blocked funds of several individuals tied to the Lebanese-based organization.
Some note the social welfare work of groups such as Hamas, which sponsors suicide bombings against Israelis, and also provides charitable aid and education to impoverished Palestinians.
"Europeans have a greater historical sympathy with the use of violence to effect political change," said Louise Richardson, an expert on European terrorism at Harvard University's Radcliffe Institute for Advanced Studies.
Most surprising in the EU's response to the war on terrorism however, was that it did not seize assets of any Europe-based groups, even though it identified 11 of them — including Spain's Basque ETA, Ireland's Real IRA and the Greece's November 17 group — as terrorist.
The EU cited a lack of legal basis. The bloc has no law explicitly permitting it to act collectively against groups based on its soil, said Cristina Gallach, spokeswoman for EU foreign affairs chief Javier Solana.
Beyond domestic groups, Europe's history of strong support for human rights makes it hard to embrace U.S. action against groups in nations with dubious rights records, such as Colombia and Turkey.
Meanwhile, the United States and some close European allies are urging the EU to reconsider its list.
Spain, which holds the rotating presidency to the EU, is pressing particularly hard because of its ongoing battle with the Basque separatist group, ETA, whose initials stand for Basque Homeland and Freedom. Battling for independence in the Basque region, ETA has waged a campaign of shootings and bombings that has left some 800 people dead over three decades.
In a move that could add fuel to Spain's push, the United States late last month expanded its anti-terror campaign by blocking assets against 21 alleged Spanish Basque separatists.
But EU diplomats say the union isn't expected to immediately follow suit on the Basques, noting that it requires unanimous approval from the 15 member governments to make changes in EU policy.
When it comes to non-Al Qaeda terrorist groups, moreover, there is little consensus on how to crack down. Even in Washington, some officials believe the United States should focus on the war in Afghanistan, and then search out other Al Qaeda cells worldwide, before expanding the war on terrorism to groups that don't target Americans.
One danger is the United States could spread its resources too thinly by targeting non-Al Qaeda terrorism, said Vincent Cannistraro, a former CIA counterterrorism chief.
"Our focus should be totally on closing down a group that is not only targeting Americans but is killing Americans," he said. "This broadening it destroys the focus."