"The rumours put about by the US administration according to which Syria, Iran and Hizbullah are seeking to destabilise the situation in Lebanon are wrong," a Syrian foreign ministry statement said.
The White House on Wednesday sounded the alarm over what it called "mounting evidence" that the militants of Hizbullah were "preparing plans to topple" the Lebanese government in collaboration with their Iranian and Syrian allies.
But spokesman Tony Snow refused to provide details or even describe the information underpinning the accusation, saying it was classified and that keeping the charge vague "serves a diplomatic purpose and an important one."
Reacting to the allegations, Hizbullah accused Washington of seeking to "turn Lebanon into a tool of the war of the (US President George W.) Bush administration against those considered enemies" -- an apparent reference to Iran and Syria.
"The latest American position is a blatant interference in a Lebanese internal affair concerning the Lebanese people's choices over their government and policies," a Hizbullah statement said.
Since its summer war with Israel, Hizbullah has called for the current Lebanese cabinet, in which it has two ministers, to be replaced with a national unity government including a Christian faction currently in opposition.
Hizbullah said "the American position is meant to obstruct the internal settlement sought by parties attempting to reach a comprehensive national solution.
"It is also meant to throw Lebanon into Washington's battle against forces and states that are friendly and brotherly to Lebanon and its people, including Iran and Syria," it said.
Before the war with Israel, Hizbullah had been involved in cross-party talks, dubbed the national dialogue, on the most controversial outstanding issues still facing Lebanon -- its fighters' weapons and relations with Syria.
But since the conflict, Hizbullah leaders have issued increasingly strident condemnations of the pro-Western politicians opposed to Syria that head the current government.
France, which currently leads UN peacekeepers deployed in Lebanon as part of a UN-brokered truce agreement, said it had no details of any plan by Syria and Iran to destabilise Lebanon, but warned against any moves in that direction.
"We have no specific details of plans of that nature," foreign ministry spokesman Denis Simonneau said.
"France, for its part, reaffirms its support for the government of (Prime Minister) Fuad Siniora and for his efforts to stabilise Lebanon and permit the rapid reconstruction of the country," he said.
France was also instrumental, with the United States, in forcing Syria to withdraw military forces from Lebanon last year.
A Saudi diplomat, meanwhile, said secret contacts were underway with political forces in Lebanon to agree on a unity government in the interest of stability.
"The kingdom is making discreet contacts and holding talks, primarily though its ambassador in Lebanon Abdel Aziz Khuja, to placate the political situation in Lebanon," the diplomat said in Riyadh on condition of anonymity.
Saudi was also working to "remove barriers to holding national dialogue talks as called for by parliament speaker Nabih Berri."
The diplomat did not rule out the possibility of "enlarging the current government, which would be a middle-of-the-road solution acceptable to all," adding that Saudi's priority was to "avoid escalating tensions within Lebanon."

Copyright AFP (Agence France-Presse), 2006