Hizbullah on Sunday blamed US interference for the Lebanese parliament's inability to elect a president and added a new condition for choosing the next head of state: The leader must support the powerful Iranian-backed Shi'ite Muslim group's fight against Israel. Hizbullah's demand is bound to further complicate efforts to elect a new president to replace Emile Lahoud who stepped down midnight Friday, plunging the crisis-ridden country into a dangerous power vacuum after rival factions failed to agree on a successor. "We want a president who believes in national participation and in the right to defend one's land and protect its people," Hizbullah's deputy leader Sheik Naim Kassem said in a speech in south Beirut. While Lebanon's US-backed government does not have relations with Israel, it also does not seek to provoke fighting between the two countries. Months of political haggling between Lebanon's rival politicians had failed to find a compromise presidential candidate to succeed Lahoud, intensifying fears of street violence between Prime Minister Fuad Saniora's Western-backed government and the opposition led by Hizbullah, which is supported by Iran and Syria. The departure of Lahoud, a staunch ally of Syria during his nine years in office, was a long-sought goal of the government installed by the majority in parliament who oppose Syria's influence in Lebanon. The government has been trying to put one of its own in the post and seal the end of Syrian dominance of Lebanon. But Hizbullah and its opposition allies have been able to stymie the government's hopes by repeatedly boycotting parliamentary votes for a new president, as they did on Friday, leaving it without the required quorum. A new parliament session to elect a president has been set for Nov. 30. In the absence of a president, Saniora's cabinet, which the opposition considers illegitimate, takes on executive power under the constitution. "This government is illegitimate and unconstitutional. It doesn't exist, so it can't rule and it can't exercise the role of the presidency," Kassem said Sunday. He also blamed U.S. "interference" for the lack of consensus in Lebanon. "American interference, through which they tried to dictate conditions (for the new president), is what blocked the consensus and kept the elections from being held on time," he said. The United States has said the new Lebanese president must be committed to implementation of international demands, a reference to UN Security Council resolutions that call for disarming Hizbullah, which Washington labels a terrorist organization. But Hizbullah leader Sheik Hassan Nasrallah earlier this month vowed to keep the group's weapons, saying no army in the world can disarm Hizbullah. Cardinal Nasrallah Sfeir, head of the influential Maronite Catholic Church, warned that a power vacuum could lead to fighting among the Lebanese and urged feuding factions to solve the presidential crisis. Under Lebanon's sectarian division of power, the president should be a Maronite. "We are in a transitional period that could lead us to stability or to chaos and infighting, God forbid," Sfeir said in his Sunday sermon. In his speech, Kassem singled out Maronite Christian opposition leader and presidential candidate Michel Aoun, who is supported by many Christians and Shi'ites, saying he was pivotal for any solution to the crisis. "The position of General Aoun is a cornerstone of any solution and, without returning to this cornerstone, there is no chance of transcending this crisis," he said. Aoun as a former army commander who fought and lost a "war of liberation" against the Syrian army in Lebanon in 1989 and continued to resist Syrian domination while living in exile in France. Syria withdrew its troops from Lebanon in 2005 following Prime Minister Rafik Hariri's assassination. Some in Lebanon accuse Syria of being behind the killing _ a charge Damascus denies. Upon his return to Lebanon in May 2005, Aoun broke with other anti-Syrian groups, whom he accuses of being corrupt and serving US interests, and struck up an alliance with Hizbullah.