"Today what happened was an attempt to kill our soldiers and policemen. This is a blow to Lebanese security. The International Tribunal is coming. Nobody will stop it. There is a conspiracy that they are making right and left."
Saad Hariri, head of Lebanon's largest Sunni political faction and leader of the country's parliamentary majority, urged supporters on Sunday to cooperate with authorities after renewed violence in northern Lebanon on Sunday.
The fighting between security forces and Fatah Islam militants left more than 30 people dead and threatens to further destabilise the country.
Lebanon is facing its worst political fall out between the Western-backed government and pro-Syrian opposition since the end of the 1975-90 civil war.
Street battles were fought in Tripoli on Sunday, a predominantly Sunni Muslim city, while guns pounded shells on a Fatah Islam stronghold located in a Palestinian refugee camp nearby.
Hariri, who met for talks with Prime Minister Fouad Saniora in Beirut, told reporters afterwards that the violence may have been linked to efforts to set up an international tribunal that would try the killers of his father, former Premier Rafik Hariri.
Hariri was assassinated in February 2005.
"This is a blow to Lebanese security. The International Tribunal is coming. Nobody will stop it," Hariri said.