The United States is warning its citizens that travel to Europe at the moment could be deadly. According to the alert, the international al-Qaeda terrorist organization has planned more attacks, with public transportation systems and other tourist venues considered likely targets.

“The State Department alerts U.S. citizens to the potential for terrorist attacks in Europe,” the alert warned. “Current information suggests that al-Qaeda and affiliated organizations continue to plan terrorist attacks.”

The warning, posted last week, also noted that “European governments have taken action to guard against a terrorist attack and some have spoken publicly about the heightened threat conditions.”

According to a report posted Sunday by the Australian ABC News network, intelligence agents recently foiled plans by an al-Qaeda-linked terror group that involved simultaneous attacks in London, France, Germany and the United States. Britain's Sky News reported that the plot was to be carried out by an unidentified Pakistan-based terrorist group.

Tourists are being warned to stay away from crowded areas. “The reports said well-armed, commando-style teams of jihadists planned to seize and murder Western hostages in a manner similar to the Mumbai attacks of 2008,” ABC News added.