A Greek-American couple were injured in a knife attack at the entrance to Athens’ Acropolis on Tuesday morning, just hours after the United States issued a worldwide caution alert urging American citizens to exercise increased vigilance due to Middle East tensions.

The attack occurred at approximately 08:05 local time, five minutes after the gates to the 5th-century BC Parthenon temple opened to visitors. The forty-eight-year-old woman sustained minor injuries to her hand whilst the fifty-three-year-old man suffered more serious injuries to his leg. Both were taken to hospital but are not in danger, according to the Greek news agency ANA.

Athens police arrested the attacker, a man in his sixties who suffers from mental health issues. Greek courts had ordered him to be admitted to a psychiatric hospital on several occasions, according to the news website News247.

The incident represents an extremely rare security breach at one of Europe’s most visited tourist sites. The Acropolis receives an average of 17 000 visitors per day during the summer peak season.

Earlier on Monday, the US State Department issued an alert warning American citizens around the world to “exercise increased caution” over the war with Iran. The alert stated that “due to heightened tensions in the Middle East, the security environment remains complex with the potential for unforeseen escalation.”

The State Department advised Americans outside the Middle East to reconsider travel to and through the region, warning of heightened possibilities of attacks targeting US diplomatic facilities “or at locations associated with the United States and Americans throughout the world.”