BEIRUT, Lebanon - Arab League chief Amr Mussa has returned to Beirut in a new bid to find a way out of the crisis gripping Lebanon after the pro-Syrian opposition raised the stakes with a call for early elections.

Mussa said he was hopeful that progress could be made in resolving a crisis that has paralysed the Lebanese government but his new mission came against the backdrop of government accusations of bad faith from the opposition.

"I have come back to resume contacts with all the parties and to make progress in my mission," the League chief said on his arrival in the Lebanese capital as opposition protests calling for the cabinet's resignation entered their 19th day.

"In this framework, I shall also be going to Damascus in the next couple of days," he added Tuesday.

Mussa, who had voiced optimism after wrapping up a previous round of talks with the feuding pro- and anti-Syrian factions last Thursday, expressed confidence that the differences could be narrowed further.

"There are some areas in which we can make progress right away," he said.

"All Arab countries are worried about the dangerous situation prevailing in Lebanon and are working to save this country."

Mussa said in Riyadh Sunday that he had briefed King Abdullah of Saudi Arabia on "efforts to resolve the Lebanese crisis.

Abdullah, whose oil-rich kingdom is a major bankroller of the Lebanese government, expressed "full support" for the mission, he added.

Mussa said he was also "in contact with the Iranians", who with Syria are the main foreign backers of the opposition, although he added that his efforts were "focussing inside Lebanon for the time being."

The Arab League chief's arrival came just 24 hours after the Hezbollah-led opposition stepped up its campaign against the rump anti-Syrian cabinet of Prime Minister Fuad Siniora with a call for early parliamentary elections under a new electoral law.

Previously the opposition had been merely been demanding that the rump cabinet left after the resignation of six pro-Syrian ministers last month make way for a government of national unity.

"The different groups of the opposition at a meeting on Monday decided to call, as a priority, for early legislative elections," pro-Syrian former premier Omar Karameh told reporters.

The governing coalition seized on the new opposition demand as proof that it was not interested in compromise.

"They forget in their enthusiasm for the idea that neither the cabinet nor parliament are under their control... and that the necessary legislation would not be approved," Communication Minister Marwan Hamadeh said.

"This demand shows the political bankruptcy of this group with putschist intentions."

The Beirut press had hailed Mussa's previous shuttle mission last week as a "half-success" that had secured a "truce" after weeks of political feuding.

But the top-selling An-Nahar newspaper warned Tuesday that the opposition's new demands were closing off any room for compromise.

"This opposition announcement amounts to an attempt to kill off the Mussa mission," the paper said.

In a sign of the mounting rift between the two sides, pro-government MPs launched a petition in parliament Tuesday accusing pro-Syrian president Emile Lahoud of violating the constitution by failing to call a by-election after the assassination of anti-Syrian industry ministry Pierre Gemayel last month.

Pro-government MP Boutros Harb said the constitution required the president to call a by-election within two months of a vacancy arising and charged that Lahoud had no grounds to refuse to countersign a government decree setting polling day for January 14.

However constitutional lawyers warned that, with just 70 MPs in the 120-seat parliament, the governing coalition lacked the two-thirds majority required to impeach the president. -AFP