LE KEF, Tunisia — Tunisia's ex-prime minister Mohamed Ghannouchi told a tribunal Monday that toppled strongman Zine El Abidine Ben Ali had wanted to kill at least 1,000 protestors demanding his exit.

Ghannouchi appeared as a witness in the trial probing manslaughter charges against Ben Ali and his key aides, held in Le Kef, some 170 kilometres (106 miles) north-west of the capital Tunis.

The military tribunal is looking into the shootings of protestors in the central-west towns of Thala and Kasserine where 22 demonstrators were killed.

The popular uprisings culminated in the demise of Ben Ali's iron-fisted rule last January and fuelled the 'Arab Spring' movement, which also ended despotic regimes in Egypt and Libya.

Ben Ali is being tried in absentia with 23 others, including two of his former interior ministers, and several top security officials, who are also accused of being responsible for injuries to hundreds in the two towns.

Former interior ministers Rafik Belhaj Kacem and Ahmed Friaa and former security chief Adel Tiouiri denied ordering security forces to shoot and passed on the blame to officials manning a security cell in the interior ministry.

They did not name any officials or pin responsibility on Ben Ali.

But Ghannouchi, who led the first transition government until February 27, testified that Ben Ali wanted to "kill a thousand or more" people demanding an end to his 23-year rule.

He said he called Ben Ali on January 9 last year to order a halt to live bullets being used on protestors in Kasserine but the former leader justified it as a legitimate defence given the attacks on police posts.

"This was Ben Ali's response to my request to stop firing live rounds," he said.

There was tension at the court with several family members of the victims, crying "Justice."

Ben Ali has been convicted of economic and other crimes by Tunisian courts and was granted exile in Saudi Arabia after his plane was denied permission to land in France.

The deposed leader is also the subject of 18 lawsuits. These include allegations of murder, conspiracy against the state and drug use.