The Islamic State (Isis) has claimed responsibility for a terror attack by gunmen on Tunis's Bardo Museum in which 23 people were killed, most of them foreign tourists.

In a three-minute audio recording released on an online forum, a man claiming to represent the extremist Sunni organisation claims it is behind the attack.

The attack is described in the recording as a "blessed invasion of one of the dens of infidels and vice in Muslim Tunisia," reports AFP.

The recording warns that the attack is the "first drop of the rain", and threatens further attacks, reports the SITE intelligence group.

No proof of Isis' involvement is offered in the recording.

Thousands of Tunisians have travelled to fight for jihadist groups including Isis in Iraq and Syria.
In the wake of the attacks, a number of pro-Isis twitter accounts hailed the attacks.

It has emerged today that one of the two gunmen, named as Yassine Laabidi and Hatem Khachnaoui, was already known to Tunisian security services.

Nine people have been arrested in the wake of the attacks, the Tunisian president's office announced today, and the army had been deployed in major cities.