Within the past several weeks, scores of suspected terrorists have been arrested or killed in Pakistan, France, and North Africa. Counterterrorism officials in the United States are focusing on the immediate threat, which appears to be a plan to attack European cities simultaneously with explosives and gunmen. But the events themselves provide a snapshot of how countries are cooperating to counter al-Qaeda and its affiliates in the nine years since September 11, the four years since London was attacked, and the two years since terrorists struck Mumbai.

"Robust information-sharing that's occurring back-and-forth across the Pond has contributed to what we know thus far, but there's more to learn," a U.S. official said. "Everyone knows the stakes are high."

The UK has developed what U.S. officials say is a new vein of human intelligence over the past several months and has shared the product with several other countries, including France and Germany. The country's signals intelligence agency, GCHQ, provided the Central Intelligence Agency with data to target Europeans believed to be part of a German-based cell that was plotting the most recent wave of attacks. The CIA, using Hellfire missiles on MQ-9 Reapers, has targeted suspected terrorists congregating in North Waziristan, Pakistan based on the new intelligence. These terrorist suspects include a Nuristani known to the U.S., a Yemeni man who helped facilitate the bombing of the U.S.S. Cole in 1998, several German nationals believed to be part of the current plots, and various Pakistanis and Chechens, according to officials.

The CIA, in turn, is sharing information about terrorist training camps and the movement of suspected jihadists into North Africa, where al-Qaeda in Islamic Maghreb rules the Sahel desert. Or they did: France has killed at least two dozen suspected militants in the past two weeks, according to U.S. officials. One official said that the United States has not played a direct role in any of the assaults, but acknowledged that a U.S. J-STARS aircraft (Joint Surveillance Target Attack Radar System) is helping French commandos and intelligence operatives pinpoint targets.

U.S. Special Operations forces are not involved in this wave of counterterrorist operations. News reports suggest that European officials don't have a high level of granularity about the nature of what terrorists might have been plotting. One military official said that the all-at-once migration of German-born Muslims to Pakistan, tracked carefully by foreign intelligence sources, was a clear sign that something was being planned. Not yet clear is whether the plan was operational.

By killing the German nationals, NATO intelligence agencies risk providing terrorists with information about how well the movement of NATO citizens going to and from Pakistan can be tracked. On the other hand, if this plot was indeed nipped well before the date of execution, it could discourage others who want to plan major attacks. And it's another sign that al-Qaeda, in whatever form it exists, has difficulty putting together attacks that pose existential threats.

Are the terrorist warnings warranted? That's the debate in France and Germany right now, as Europeans have been sensitized to the idea that governments might hype terrorist threats for reasons having little to do with terrorism.

This weekend, when new White House Chief of Staff Peter Rouse convened a meeting of senior intelligence and counter-intelligence officials, two questions were debated: How real is the threat to Europe? And, if real, does the U.S. government have the responsibility to formally warn its citizens who travel there? The National Security Staff answered both questions in the affirmative, but the warning, which was relatively light, reflects the intelligence gathered about the plot.

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