Tunisia has arrested seven people in connection with Friday’s seaside terrorist attack that left 38 people dead.

The seven suspects are currently being interrogated in the capital city, Tunis, according to a source with knowledge of the investigation.

The unnamed source said four of the suspects were arrested on Monday; two in the resort town of Sousse, where the attack occurred, one in Tunis, and one in the city of Kasserine. Three others had been taken into custody a day before.

The source spoke on condition of anonymity because he was not authorized to be publicly named.

Earlier, Interior Minister Mohamed Najem Gharsalli said those arrested were members of a network that was behind the assault, but provided no more details.

Gharsalli made the comment in a meeting with British, French, German and Belgian interior ministers who were in Tunisia to pay tribute to victims of the attack.

The minister went on to say that Tunis was determined to fight terrorism in all its forms.

On Friday, a Tunisian student disguised as a tourist used an MK 47 assault rifle to kill tourists at a hotel in Port El Kantaoui, near Sousse to the south of Tunis.

Eyewitnesses said the gunman was mowing down screaming tourists as they ran for their lives.

The gunman, who was shot dead by police, yelled to locals to stay away, adding, “I didn't come for you."

Among the 38 victims there are tourists from Germany, Belgium and Portugal; however, most of the tourists killed were from the UK.

"Eighteen British nationals were killed, but we are expecting this number to rise further and that will be around 30," the UK prime minister’s spokesperson said on Monday, adding that all the 25 injured Britons would be evacuated "within 24 hours".

Three months ago, another terrorist attack claimed the lives of 21 tourists and a policeman at the Bardo National Museum in Tunis.

Both terrorist attacks, the recent strike and the previous one, were carried out by members of the ISIL Takfiri group.

ISIL has currently occupied huge parts of Syria and Iraq and carried out numerous terrorist attacks and heinous crimes there and elsewhere around the world.