Europe is on high alert over concerns that terrorists based in Pakistan have been planning Mumbai-style attacks in London and other cities, Sky News reported Tuesday.
A Western counterterrorism official said some missile strikes in a surge of attacks by unmanned U.S. drones in Pakistan were aimed at disrupting the plots.
Intelligence agencies have intercepted information suggesting that a group thought to be linked to al-Qaida has been planning attacks in Britain, France and Germany, sources told Sky News.
Four U.S. security officials, who asked for anonymity when discussing sensitive information, told Reuters that initial intelligence reports about the threat first surfaced roughly two weeks ago, around the time of the anniversary of the September 11, 2001, attacks on the United States.
The alleged plot was thought to be in the "advanced but not imminent stage," Sky News said.
According to Sky News, the plot involved planned attacks similar to the commando-style raids carried out in Mumbai, India's second-largest city, by Islamic terrorists in 2008.
The attacks left 174 people — including nine gunmen — dead, and sullied relations between India and Pakistan. India has blamed Pakistan-based militants Lashkar-e-Taiba for the attacks.
The new European plot was unearthed after intelligence sharing between London, France, Germany and the U.S., Sky News reported. The discovery of the plot could explain why the CIA has been dramatically stepping up drone attacks on alleged militants in the mountains of Pakistan in recent weeks, Sky News said.
The Western counterterrorism official said the targeted strikes were aimed at al-Qaida and other militant groups arrayed in Pakistan's tribal region near the Afghanistan border. The official spoke on condition of anonymity because the details of the terrorism plot remain sensitive.
The Obama administration has intensified the use of drone-fired missiles in Pakistan's border area but this month there have been at least 21 attacks, more than double the highest number fired in any other single month.
A suspected American missile strike killed four militants in northwest Pakistan on Tuesday, intelligence officials said. There was no word on the identities of those killed in the attack in South Waziristan region, which lies just across the border from Afghanistan. The Pakistani army last year launched a major antimilitant offensive in the region, though insurgents remain.
Word of the alleged plot came as the Eiffel Tower in Paris was briefly evacuated Tuesday after officials received a bomb threat called in from a telephone booth in the second such alert at the landmark tourist attraction in two weeks. No bomb was found.
French National Police Chief Frederic Pechenard said last week that authorities suspect al-Qaida's North African branch of plotting a bomb attack on a crowded location in France. His warning came after al-Qaida in the Islamic Maghreb, or AQIM, claimed responsibility for the Sept. 16 abduction of five French nationals and two Africans in northern Niger.
U.S. counterterrorism officials told NBC News that while there is "historical concern" that terrorists could carry "Mumbai-style" attacks in Europe, there is no specific intelligence that such attacks are in the offing.
Western intelligence agencies believe al-Qaida in the Islamic Maghreb is planning attacks in Europe but they do not have specificity on the date, location or mode of attack, according to NBC News.