A Tunisian policeman was shot dead Wednesday by two assailants on a motorbike in the coastal resort of Sousse where an extremist gunman killed 38 tourists in June.

A Tunisian policeman was shot dead Wednesday by two assailants on a motorbike in the coastal resort of Sousse where an extremist gunman killed 38 tourists in June, a senior security official said.

"Unknown assailants fired on three policemen on a road. One of them was hit and died in hospital," Rafik Chelly, secretary of state for national security, told AFP.

"An investigation is under way. We can't say any more," said Chelly, without being able to clarify if the attack was the work of Takfiris.

An interior ministry spokesman said the two other policemen were unharmed, contrary to an earlier report from Wataniya-1 television.

The incident took place seven kilometers (five miles) from Sousse, he said, adding police were hunting the assailants who fled.

The targeted policemen were waiting by the side of the road for a ride to a town in central Tunisia, according to the television.

The attack came less than two months after an extremist gunman killed 30 Britons and eight other foreign tourists on a beach in Sousse, in an attack claimed by the Takfiri group, ISIL (so-called Islamic State in Iraq and Levant).

Tunisia has been under a state of emergency in the wake of the June 26 massacre which followed an attack by gunmen on the Bardo museum in Tunis that killed 21 foreign tourists and a policeman.

ISIL also claimed responsibility for the March 18 museum attack, and extra troops have been posted at tourist sites since the beach killings.

Tunisia has since its 2011 revolution faced an upsurge in Takfiri violence that has cost the lives of dozens of soldiers and police, with most attacks claimed by Al-Qaeda's North African branch.