An attacker targeted the US embassy in the Tunisian capital on Friday, causing an explosion and injuries among police before being killed, police said.
The attacker tried to enter the embassy but was prevented by police who guarded the diplomatic mission in the Berges du Lac district, a police official said.
Several police were wounded in the attack, the official added, without giving further details.
"The operation was doomed to fail," he said. Police said the attacker had been riding a motorcycle.
They did not immediately confirm if it was a suicide attack, but body parts were seen strewn on the ground at the scene.
The explosion caused panic among pedestrians near the embassy, images shared online showed.
Tunisia faced a rise in jihadist activity after its 2011 revolution, with attacks killing dozens of security personnel, civilians and foreign tourists.
While the security situation has significantly improved since a series of deadly attacks in 2015, Tunisia has maintained a state of emergency for four years and assaults against security forces have persisted.