Mouna Guebla, 30, was an unemployed graduate from the eastern region of Mahdia, the prosecutor's office said.

Her father doubted that his daughter had acted willingly to carry out the attack.

Guebla appeared to have used a homemade bomb rather than an explosive belt, police sources told AFP news agency.

After studying English, Guebla had been jobless for three years, helping to look after sheep to assist her family. A third of Tunisian graduates are unemployed.

"I know she did not intend to do things like that," her father, Mouhamed Guebla, was quoted as saying by AFP news agency.

The attack was an "isolated act", Interior Minister Hichem Fourati said, adding that Guebla had not been on a watch list of potential extremists and not been "known for her religious background or affiliation".

No group has said it was behind the attack but local media report that Guebla might have been radicalised on the internet.

Normalcy returned to Tunis on Tuesday but there was a reinforced police presence around the blast site.

Authorities say nobody was seriously injured in the attack.

The attack comes at a time when the country's vital tourism industry is starting to show signs of recovery, more than three years after two deadly terror attacks decimated visitor numbers.

The first, an attack on the capital's Bardo Museum in March 2015, left 22 people dead. Just a few months later, in June, another 38 people were killed in a resort in Sousse.

Tunisia has been under a state of emergency since 2015 when a suicide bomber killed 12 security agents on a bus for presidential guards, AFP reports.

This state of emergency was extended earlier this month until November 6, ahead of elections planned for next year, the agency adds.