Murder of engineer planned abroad - minister

"It is possible that a foreign service is implicated but... we do not yet have any tangible proof," Majdoub told a news conference after attending a security meeting with the prime minister.

But he said that the December 15 murder of Mohamed Zaouari had been planned as far back as June in the Austrian capital Vienna and in the Hungarian capital Budapest.

Zaouari, 49, was murdered at the wheel of his car outside his house in Tunisia's second city Sfax on Thursday. He was hit by 20 bullets.

Al-Qassam Martyrs Brigade, the armed wing of Hamas that controls the Gaza Strip, told AFP on Saturday that Zaouari was a drone expert and was killed by "Zionist treachery", referring to Israel.

It said Zaouari had worked for the "resistance" for 10 years.

Israel has made no comment about the Hamas accusation.

On Sunday, the Tunisian government said a probe into the shooting indicated that "foreign elements" were involved, without giving further details.

The prosecution has said that 10 suspects, all Tunisians, have been detained for questioning, including a female journalist, and that authorities have seized four vehicles and two weapons.

Parliament is to meet to discuss the murder of Zaouari, after the government said it was determined to "pursue those guilty of carrying out assassinations inside and outside" the country.

Political parties have called for a protest on Tuesday in central Tunis to denounce the murder, and the engineers' union said it will observe "a day of wrath" on Thursday.