Tunisian police seized five tonnes of cannabis on a yacht and arrested three European nationals, in a record drugs haul for the North African country, the interior ministry said Tuesday.

"Three tonnes were seized at first on Sunday and then another two tons were found on the yacht" in the coastal resort of Yasmine-Hammamet, south of Tunis, ministry spokesman Mohamed Ali Aroui told Agence France-Presse.

The loss of a "child of Tunisia" has plunged its small Jewish community into mourning after Yoav Hattab, son of a Tunis rabbi, was killed in last week's jihadist attack on a Paris kosher supermarket.

Hattab, a 21-year-old who was in France for international business studies, had a bright future in front of him.

Around 300 people demonstrated in central Tunis Friday in solidarity with two journalists the Libyan branch of the Islamic State (IS) group claims it has executed.

"We are all Sofiene, we are all Nadhir," read placards held by the demonstrators, many of them young journalists, in reference to Sofiene Chourabi and Nadhir Ktari.

The Libyan branch of the Islamic State jihadist group claimed Thursday to have killed two Tunisian journalists who went missing in September.

In a statement released on jihadist websites showing images of Sofiene Chourabi and Nadhir Ktari, the group said it had "applied the law of Allah" against them. 

A Tunisian military court Tuesday denied bail for a blogger who is appealing his three-year jail sentence for defaming the army -- a case that has alarmed rights campaigners.

The court scheduled the next hearing for Yassine Ayari on January 20.

U.S. President Barack Obama has invited Tunisia's first democratically elected president to visit Washington, the White House said Monday.

Beji Caid Essebsi won Tunisia's first free presidential election last month. The revolution that toppled long-time ruler Zine El Abidine Ben Ali four years ago unleashed the so called Arab Spring.

Ex-interior minister Habib Essid, who held a number of posts under Tunisia's ousted regime, has been tasked with forming a government as prime minister designate, he announced Monday.

Essid, a top interior ministry civil servant under toppled dictator Zine El Abidine Ben Ali, made the announcement after a meeting with Beji Caid Essebsi who last month won Tunisia's first free presidential election.

Suspected Islamist extremists slit the throat of a Tunisian policeman south of the capital overnight, the interior ministry said on Sunday.

Since the revolution of January 2011, Tunisia has seen a rise in Islamist extremism and tackling it is one of the main challenges facing  the country's first freely elected President Beji Caid Essebsi who was sworn in on Wednesday.

Media watchdog Reporters Without Borders (RSF) expressed "deep concern" on Friday after a military court sentenced a Tunisian blogger to three years in jail for defaming army officers.

"RSF expresses its deep concern after blogger Yassine Ayari was sentenced in absentia", it said in a statement, calling for his case to be transferred to a civilian court that would "guarantee impartiality and independence".

Anti-Islamist Beji Caid Essebsi, 88, was sworn in Wednesday as Tunisia's first freely elected president vowing to work for national reconciliation, four years after an uprising that sparked the Arab Spring.

The election of Essebsi, a veteran of previous regimes, is seen as a landmark for the North African nation, where longtime dictator Zine El Abidine Ben Ali was toppled in 2011.