Western intelligence agencies are reportedly tracking a plot to carry out terrorist attacks in Britain, France, and Germany.
Citing unidentified intelligence and security officials in the United States and Europe, Western media reported that the potential attacks were allegedly being planned from Pakistan.
The BBC said it was "one of the most serious Al-Qaeda attack plans in recent years" and was inspired by the terror group's leadership in Pakistan's tribal areas.
The broadcaster said it was thought commando-style teams of jihadists planned to seize Western hostages and murder them. It said the idea was thought to have moved from the aspirational stage to actual planning.
But the plot was not believed to be imminent, and national threat levels have not been upgraded yet.
Britain's Sky News television reported that intelligence-sharing between the three European states and the United States had led to the attack plans being uncovered and disrupted.
In the United States, ABC News reported that the source of the threat information was a suspected German terrorist captured on his way to Europe and now being held in Afghanistan. U.S. officials confirmed that a detainee at Bagram airbase holds a German passport.
ABC cited U.S. officials as saying that country was also a possible target.
European officials did not confirm the plot, but the reports come as Britain, France, and Germany are on a heightened state of security alert.
The German Interior Ministry said in a statement that it knew Al-Qaeda had long-term plans to target Europe and that this information had been exchanged with other countries with the requisite "sensitivity and intensity." But it added that there were "no concrete pointers to imminent attacks in Germany stemming from this."
The director-general of Britain's MI5 Security Service, Jonathan Evans, said on September 16 that there remained "a serious risk of a lethal attack taking place."
In the United States, Homeland Security Secretary Janet Napolitano on September 22 said that "increased activity" by terror groups signaled a heightened threat against Western countries, including European states.
Concern about a possible attack has risen in Paris, where the Eiffel Tower was evacuated on September 28 following the second hoax bomb threat at the landmark in a month.
Interior Minister Brice Hortefeux on September 20 warned that France faced a "real" threat amid a backlash from Al-Qaeda militants in the Maghreb, with concerns growing of an attack on French soil.
"I won't answer any other question, but I would confirm that the [terrorist] threat is real, that our vigilance is reinforced, that the terror alert level is 'red' reinforced, meaning the penultimate highest ranking," Hortefeux said.
In a statement on September 28, U.S. National Intelligence Director James Clapper did not comment directly on any European plot but insisted: "We know Al-Qaeda wants to attack Europe and the United States."
"The Wall Street Journal" reported that the CIA had stepped up its drone attacks in lawless parts of Pakistan as part of efforts to prevent attacks on European cities.
But "The Washington Post" quoted U.S. officials as describing the threat of such attacks in Europe as "credible but not specific."
Pakistan's army has dismissed as "very speculative" media reports that this month's upsurge in U.S. drone strikes sought to disrupt attacks on European cities.
Military spokesman Major General Athar Abbas told Reuters: "We don't have any information or intelligence that militants had gathered [in northwestern Pakistan] and were plotting attacks. There is absolutely no intelligence on that."
Pakistani security officials have reported around 20 drone strikes in the country's tribal belt along the Afghan border this month -- more than double the number fired in any previous month.
NATO has confirmed that senior Al-Qaeda commander Abdallah Umar al-Qurayshi was killed along with several other militants by an air strike over the weekend.
Pakistan is also investigating reports that a U.S. drone missile strike killed another senior Al-Qaeda commander, Sheikh Fateh al-Masri, on September 25 as he traveled in a tribal region near the Afghan border.
based on agency reports