DOHA (Reuters) – Rival Lebanese leaders made some progress on the third day of talks in Qatar on Sunday but tough obstacles remained before a deal could be clinched to pull Lebanon back from the brink of a new civil war.

Qatari Prime Minister Sheikh Hamad bin Jassim bin Jabr al-Thani held intensive meetings with leaders of the U.S.-backed ruling coalition and Iranian and Syrian allies in the opposition to try to end a crisis that has paralysed the government for 18 months and left Lebanon with no president since November.

But Sheikh Hamad had yet to win final approval from both sides on one of the prickliest issues on the agenda — the shape of a new government, delegates said. The Qatari leader’s latest proposal suggested dividing cabinet seats three ways equally — a third for each side and a third for the new president.

Delegates said the opposition had agreed to the proposal but the ruling coalition was still waiting for agreement on other issues before giving a final answer.

A six-member committee created on Saturday to lay the framework for a new election law made progress early on but was later stuck on how to divide Beirut electorally.

The Lebanese capital is a stronghold of the ruling coalition but its Sunni Muslim supporters have been on the defensive since Hezbollah briefly seized parts of the city in the worst internal fighting since the 1975-1990 civil war.

Officials from the governing coalition were also demanding clear guarantees that Hezbollah would not turn its weapons against them again and that the fate of its arms would be discussed soon, delegates said.

“There has been some progress here and there, but some major issues remain,” one senior delegate said.

DEFINING MOMENT

Washington blames Syria and Iran for Hezbollah’s offensive last week which forced the government to rescind two decisions that had triggered the escalation.

Arab mediators clinched a deal on Thursday to end the fighting and pave the way for the talks in Doha.

But the violence, which killed 81 people, has deepened mistrust among rival politicians and exacerbated sectarian tensions between Shi’ites loyal to Hezbollah and Druze and Sunni followers of the ruling coalition.

President George W. Bush said on Saturday the United States would stand by the Lebanese government against Hezbollah and accused “radical elements” of trying to undermine democracy.

“It’s a defining moment,” he told reporters in Sharm el-Sheikh during a visit to Egypt.

There has been no deadline set for the talks but diplomats say that unless some progress is made in the next day or two then a deal might prove tough to reach.

Power-sharing in a new government and the basis of an election law are the core issues on the agenda.

The Hezbollah-led opposition wants more say in a cabinet controlled by factions opposed to Syrian influence in Lebanon.

The ruling coalition’s refusal to yield to the demand for an effective veto power in the cabinet triggered the resignation of all Shi’ite ministers in November 2006, crippling a political system built around the delicate sectarian balance.

Election laws have always been a sensitive subject in Lebanon, a patchwork of religious sects where redrawing constituencies can have a dramatic impact on voting results.

A deal would lead to the election of army commander General Michel Suleiman as president. Both sides have accepted his nomination for a post reserved for a Maronite Christian in Lebanon’s sectarian power-sharing system.