Europe will see fewer American tourists this summer asUS citizens are being warned of the potential risks of travelling to and throughout Europe.

The State Department issued an alert following Tuesday’s triple-bombing in Brussels which claimed 34 lives.

It said: “Terrorist groups continue to plan near-term attacks throughout Europe, targeting sporting events, tourist sites, restaurants, and transportation.

“US citizens should exercise vigilance when in public places or using mass transportation. Be aware of immediate surroundings and avoid crowded places. Exercise particular caution during religious holidays and at large festivals or events.”