The Der Spiegel report quoted an unnamed source as saying that the UN-backed tribunal into the assassination had found evidence which suggested Hezbollah had a role in attack.

Al-Hariri, a Sunni Muslim construction magnate who had been Lebanon's prime minister on two occasions, was killed with 22 other people in a bomb attack in Beirut in February 2005.

'Hezbollah link'

The Der Spiegel report quoted an unnamed source close to the UN tribunal as saying that Lebanese investigators found a link between eight mobile phones used at the time of the bombing and a network of 20 other phones belonging to Hezbollah agents.

In depth


 Profile: Rafiq al-Hariri
 Timeline: Al-Hariri investigation
 Split remains over Hariri tribunal

The report named the suspected mastermind of the attack as Hajj Salim, believed to be the commander of the Islamic Resistance, Hezbollah's military wing.

Responding to the report, Israel's foreign minister said that an international arrest warrant should be issued for Hassan Nasrallah, Hezbollah's secretary-general.

"The report in Der Spiegel on Nasrallah's direct involvement in the assassination of Hariri should raise concern in the entire international community," Avigdor Lieberman said.

"He should have an international arrest warrant issued against  him, and if not, he should be arrested by force," he said.

Syria implicated

Prior to the formation of the special tribunal, interim reports from investigators leading the UN Independent Investigation Commission suggested that Lebanese and Syrian security officials may have planned the killing of al-Hariri.

Nasrallah said that the Der Spiegel report was 'very, very, very dangerous' [AFP]
At the time of al-Hariri's death, Damascus had thousands of troops and intelligence officers deployed in Lebanon.

Widespread public anger in Lebanon after the assassination led Syria to pull its forces out of Lebanon in April 2005, ending a 29-year presence in the country.

Damascus dismissed the Der Spiegel report as "insignificant".

"I invite the prosecutor to use his prerogatives concerning these lies which undermine the international investigation," Walid Muallem, Syria's foreign minister, said.

The Der Spiegel report comes before a June 7 parliamentary election in Lebanon, in which a Western-backed parliamentary majority faces a bloc led by Hezbollah, which is supported by Iran and Syria.

"This is a pure fabrication aimed at influencing the [forthcoming Lebanese] election campaign and to deflect attention from the news about the dismantling of spy networks working for Israel," a Hezbollah statement released on al-Manar television said on Sunday.