European and U.S. intelligence officials say they have discovered a plot to launch commando-style terrorist attacks in Britain, France, Germany and possibly the United States.
The officials gave no specifics on what they found out, other than saying the threat is credible.
But U.S. and British news reports say the attacks would have been similar to the 2008 terrorist attacks in India, when Islamic militants took over multiple sites across Mumbai, including the Taj Hotel.
Intelligence officials reportedly learned about the planned attacks from a German terror suspect arrested in July and currently believed to be in U.S. custody in Afghanistan.
News of the plot came as Paris police evacuated the Eiffel Tower Tuesday for the second time this month, because of a bomb threat.
Nothing was found after a two-hour search.
French authorities have warned of an imminent terror attack, but it is unclear if Tuesday's bomb threat was connected with the terror plot.
Some information for this report was provided by AFP, AP and Reuters.
