An interior ministry spokesman said police opened fire on the man, whom authorities described as a wanted militant named Aymen Smiri, according to Reuters. The spokesman noted that there were no other casualties.
Earlier Reuters reported, citing witnesses, that a man had blown himself up after being surrounded by police.
According to multiple reports, the suicide bomber blew himself up between the Al Intilaka and Ettadhamen neigbourhoods.
Netizens shared the name of the alleged bomber and posted purported maps of the site.
No further details were immediately available.
No group has claimed responsibility for the attack.
Last week, two suicide bombers targeted the Tunisian capital. The first occurred in the proximity of the French embassy, leaving two police officers and three civilians injured. A second suicide blast rocked Tunis after a bomber blew themselves up near a police station in al-Qarjani district.
Central Tunis has been rocked by suicide blasts several times in recent years. The country has been struggling with a threat posed by militant groups active in remote areas bordering Algeria following the 2011 ouster of President Zine Abidine Ben Ali.
Tunisia, which relies heavily on tourism, has beefed up security measures since a series of attacks in 2015, including an attack on the museum of Bardo in which 21 people were killed, and another attack in the resort of Sousse, which killed 38 people.