A U.S. missile killed five German militants taking shelter in a house in northwest Pakistan on Monday, intelligence officials said. The attack hit a house in North Waziristan. That region has been named as the source of a European terror plot that has prompted American authorities to issue a travel advisory. One or more German citizens are reported to be linked to the plot. The missile strike took place in the town of Mir Ali, a known hub for foreign militants with links to al-Qaida. Two officers said the five victims were believed to be German citizens in the region for terrorist training. A third said they were believed to be foreigners, but gave no details. The officials spoke anonymously because their agency does not permit operatives to be named in the media. Killing so many foreign militants in a single strike would be unusual. U.S. officials rarely confirm the identities of those who are being targeted by the CIA-led missile campaign. Sometimes information given by intelligence officials turns out to be false. More often than not it is never confirmed or denied. Sometimes militant organizations announce the names of those killed, but typically not for weeks or months. Last month, American spy planes carried out 21 missile attacks in northwest Pakistan, more than twice the highest number in any previous month over the last six years.