The US State Department could issue a "travel alert" for Europe as early as Sunday in light of a heightened threat of terrorist attacks, US media reported.
The Washington Post said the US government would issue the alert, rather than a stronger warning because there were no specific locations US travellers should avoid. The alert was expected to urge traveller to exercise caution in popular tourist destinations, dpa reported.
US and European intelligence agencies have uncovered a potential al-Qaeda-led terrorist plot to attack cities in Britain, France and Germany, reports said Wednesday.
The intended simultaneous attacks were being allegedly planned from Pakistan and are believed to have reached advanced stages but were not imminent.