If you must travel, the State Dept recommends being aware of your surroundings when traveling to tourist locations and crowded public venues, among other precautions.

“Terrorists may attack with little or no warning,” the State Department noted. In late March, Canada also advised travelers to “exercise a high degree of caution in Germany due to the threat of terrorism.” The United Kingdom’s foreign travel advice additionally cited incidents of terror in Germany in recent years.

The U.S. State Department on Wednesday warned that travelers to Germany should exercise increased caution while visiting the central European nation.