A leaked report blaming Hezbollah for the assassination of a former Lebanese prime minister has reignited tensions between Sunnis and Shias ahead of a next month’s parliamentary elections.

The German magazine Der Spiegel reported at the weekend that the international tribunal established to find the killers of Rafik Hariri has uncovered evidence that Hezbollah’s “special operational unit” was responsible for the February 2005 truck bomb assassination.

Quoting an unnamed source, it said that Lebanese investigators had identified some 20 mobile phones used in the planning of the attack and traced them all to Hezbollah militants. The magazine suggested that Hezbollah’s motive for killing Mr Hariri lay in the former prime minister’s rising popularity which was a “thorn in the side” of Sheikh Hassan Nasrallah, Hezbollah’s leader.

The leak appeared to be a calculated move to put Hezbollah on the defensive just as it was hoping that its anticipated election victory would earn it some respite from international and domestic pressure to dismantle its military wing.

The Hezbollah-led opposition looked set to secure a narrow victory in the June 7 poll, allowing it to form the backbone of the next government.

Such an outcome would embolden Iran and Syria, which support the militant Shia Hezbollah, and dismay the United States and so-called moderate Arab countries, such as Saudi Arabia and Egypt which fret at Tehran’s rising influence in the region.

It could also inflame anti-Shia sentiment among Lebanese Sunnis who are still smarting from their defeat at the hands of Hezbollah fighters in street clashes in Beirut a year ago.

Syria has been widely regarded as the chief suspect in Mr Hariri’s murder, but Der Spiegel said that while the United Nations-led investigation has not cleared Damascus, Bashar al-Assad, the Syrian President, “is no longer in the line of fire”.

Hezbollah described the allegations as “evil fabrications” aimed at “influencing the election campaign” and demanded a retraction from the tribunal.

Nawaf Mussawi, a Hezbollah electoral candidate, warned: “The campaign launched by some parties against the resistance paves the way for the assassination operation that Israel is preparing” against Sheikh Nasrallah.

A spokeswoman for the tribunal based in The Hague refused to discuss the Spiegel article, saying “We don’t know where they are getting the story from”.

The Western-backed March 14 coalition, the current parliamentary majority, appears to be reacting cautiously to the story, apparently wary of stoking sectarian tensions ahead of the elections.

A spokesman for Saad Hariri, Rafik Hariri’s son and political heir who heads the Sunni Future Movement, told The Times: “We do not comment on any information regarding the tribunal unless it is officially stated by the tribunal”.

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