New York - The United Nations said Thursday Hezbollah forces have become a major armed militia group challenging Lebanon's sovereignty despite repeated UN demands for it to disarm and disband.

The Beirut government has informed the UN that the Iranian-backed Hezbollah is maintaining a "massive para-military infrastructure separate from the state," Terge Roed-Larsen, a UN special envoy for Lebanon, told the UN Security Council in an open meeting.

The continued presence of Lebanese and non-Lebanese militias, of which Hezbollah is the most significant group, is a challenge to Lebanon as it is going through a major political crisis created by a vacuum in the top leadership, Roed-Larsen said.

The government has failed to elect a new president despite more than a dozen tries, and the post is vacant since last November.

Hezbollah has developed a secure communication network separate from the Lebanese government, covering vast areas south of the Litany River, the entire Mediterranean coastline to the border with Syria, the Palestinian camps south of Beirut and the Bekaa Valley, the council was told.

Hezbollah has its own system of surveillance cameras at Beirut airport, which prompted the government to dismiss Brigadier General Wafiq Shoucair, the airport security commander.

Roed-Larsen said another concern for Beirut is the activities of the Popular Front for the Liberation of Palestine-General Command (PFLP-GC) and the Fatah Al-Intifada, both of which have para-military infrastructure outside refugee camps and along the Lebanese-Syria border.

"The government of Syria bears the responsibility in urging these groups to abide by Security Council resolutions and the decisions of the Lebanese government," he said.

The 15-nation council in 2004 adopted resolution 1559, demanding the withdrawal of Syria from Lebanon and disarmament of militias. Syria formally pulled its military and intelligence forces out of the country in 2005 after more than three decades in Lebanon, but is still believed to heavily influence events in Lebanon.

Roed-Larsen's report to the council said that resolution 1559 has not been respected and implemented because of the continued presence of armed militias and violations of Lebanese airspace by Israeli jet fighters carried out under security claims. (dpa)