Lebanon (search) has yet to achieve "tangible results" in meeting U.N. demands to disarm Palestinian and Lebanese militias — a reference to the Hezbollah guerrilla group, a top envoy said in a report Wednesday.

The envoy, Terje Roed-Larsen (search), said Lebanon's inability to exert control over some areas or rein in the militias was stalling its progress toward achieving full sovereignty after emerging from nearly three decades of dominance by Syria.

"Tangible results are yet to be achieved in these two fields, and I will continue my efforts in this regard," he wrote.

Roed-Larsen's report said considerable progress had been made toward meeting other parts of Resolution 1559, which called for Syria (search) to withdraw all military forces and intelligence operatives as well as the disarmament of all Lebanese militias.

The report is likely to increase pressure on Syria as the United States, France and Britain challenged the rest of the U.N. Security Council to adopt a tough new resolution threatening sanctions if Damascus doesn't cooperate fully with a U.N. investigation into the assassination of former Lebanese prime minister Rafik Hariri (search).

There are allegations Syria is continuing to smuggle arms to Palestinian militia groups in Lebanese refugee camps, in violation of the September 2004 council resolution. Roed-Larsen is U.N. Secretary-General Kofi Annan's special envoy for implementation of the resolution.

Syria withdrew its troops and intelligence officials last April, ending the country's 29-year presence in its smaller neighbor which began when Damascus sent troops to help quell what was then a year-old civil war.

While resolution 1559 was adopted a year ago, it was Hariri's assassination, and the massive anti-Syrian protests it sparked, that spurred the Syrians to leave.

While that step has been encouraging, the requirement to disarm — a clear reference to the Syrian- and Iranian-backed guerrilla group Hezbollah — has not been met, Roed-Larsen said. There also has been little significant change in Lebanon's ability to gain control over all its territory.

A draft resolution circulated late Tuesday by the United States, France and Britain strongly backs a report by the U.N. investigating commission that implicated top Syrian and Lebanese security officials in Hariri's assassination and accused Syria of not cooperating fully with the probe.

The report brought swift denials from the Syrian government, which called it biased, politicized and an American plot to take over the region.

Russia and China, which have veto power on the Security Council, and Algeria, the only Arab member, have been hesitant to use the threat of sanctions to back up a call for more Syrian cooperation.

Syria's U.N. Ambassador Fayssal Mekdad told the council that every paragraph in the report deserved to be refuted. He insisted Syria "has cooperated faithfully and sincerely" and will continue to do so.

If adopted, the draft resolution would require Syria to detain anyone the U.N. investigators consider a suspect and allow the individual to be questioned outside the country or without Syrian officials present. It would also immediately freeze the assets and impose a travel ban on anyone identified as a suspect by the commission.

The language appeared to be an effort to pressure Syria into giving the investigators access to top security officials — possibly including the brother-in-law and brother of President Bashar Assad — who may be implicated in Hariri's slaying.

Syria would also be required to renounce terrorism and "commit itself definitively to cease all support for all forms of terrorist action and all assistance to terrorist groups and to demonstrate this undertaking through concrete actions."

If Syria does not fully cooperate with the investigation, the draft says the council intends to consider "further measures," including sanctions, "to ensure compliance by Syria."

"We want a very strong signal to the government of Syria that its obstruction has to cease and cease immediately," U.S. Ambassador John Bolton said.

Council experts are expected to discuss the resolution over the next few days and Bolton said ministers from the 15 council nations will likely come to New York on Monday, hopefully to adopt it. Diplomats said a ministerial meeting would add clout to the resolution and increase pressure on Syria.