TUNIS (AFP) - The brother of a shepherd whose beheading by jihadists outraged Tunisia has himself been found dead after being abducted, media reports and the defence minister's spokesman said on Saturday (June 3).

Khalifa Soltani was kidnapped on Friday in the Mount Mghilla area, and a security sweep recovered his body after a "terrorist group" announced his abduction, Belhassen Oueslati told AFP.

The Islamic State in Iraq and Syria (ISIS) group claimed responsibility, according to the SITE Intelligence Group which monitors extremist organisations.

It quoted the ISIS Amaq agency as saying the man killed on Friday was a "spy... who worked for the benefit of the Tunisian intelligence on Mount Mghilla".

Oueslati did not provide further details about the victim, but media reports said he was the brother of Mabrouk Soltani, a 16-year-old shepherd who was decapitated on Nov 13, 2015.

The Tunisian branch of ISIS, Jund al-Khilafa (soldiers of the caliphate), claimed that killing, accusing the boy of betraying their movements to the army.

The circumstances of the latest death were not immediately known.

Nessma television said Khalifa Soltani's body was taken to a hospital in the central Kasserine region for an autopsy.

Prime Minister Youssef Chahed has called for a manhunt for the perpetrators and asked Defence Minister Farhat Horchani to head to the area, the channel said.

The leftist Popular Front, meanwhile, called for a demonstration later on Saturday in Tunis "to denounce terrorism" and show solidarity with the Soltani family.

His killing comes less than a week after a top jihadist was shot and six others arrested in the Kasserine region's Mount Salloum area near the border with Algeria.

The interior ministry said on Tuesday the six belonged to "sleeper cells" of Jund al-Khilafa.

It also said the jihadist killed on Sunday had belonged to the Okba Ibn Nafaa Battalion which is linked to Al-Qaeda, and not to ISIS as it had previously said.

Since its 2011 revolution, Tunisia has experienced an increase in jihadist attacks that have cost the lives of dozens of members of the security forces and 59 foreign tourists.

The country has been under a state of emergency since November 2015, when a suicide bombing in Tunis claimed by ISIS killed 12 presidential guards.