DAMASCUS (AFP) -- Peace envoy Kofi Annan is pushing a plan for an interim government for Syria to include representatives of both sides in the conflict ahead of an international conference on Saturday, diplomats said.

The weekend meeting in Geneva, which was agreed only after wrangling between Moscow and Washington over both the agenda and the guest list, is to be attended by some regional governments but not by rival Middle East heavywights Iran and Saudi Arabia, diplomats said.

The diplomatic push came as the death toll in Syria soared, with 149 people killed on Wednesday alone on the heels if what human rights monitors said was the bloodiest week of the 15-month uprising against President Bashar al-Assad‘s rule.

Annan’s proposed interim authority would exclude officials whose presence might jeopardize the transition “or undermine efforts to bring reconciliation,” according to a summary given by one U.N. diplomat.

The major powers -- the U.S., Britain, France, China and Russia, a key Assad ally -- generally back the plan that will be discussed at a meeting of foreign ministers Annan has convened in Geneva on Saturday, the diplomats said.

“The language of Annan‘s plan suggests that Assad could be excluded but also that certain opposition figures could be ruled out,” said a second U.N. diplomat, while stressing that there was nothing there that automatically excluded him.

“Russia’s acceptance of this plan could be a new sign that it is ready to let Assad go,” said the diplomat.

But Russia‘s U.N. ambassador Vitaly Churkin said there was no guarantee that Annan’s document would be agreed to in Geneva.

“Whatever Kofi Annan is going to prepare is going to be basis of discussion for the ministers,” he told reporters.

Turkey, Qatar, Kuwait and Iraq will be at the meeting, but Iran and Saudi Arabia are not invited.

Both Annan and U.N. chief Ban Ki-moon had wanted Iran to take part in the talks, as had Russia. But the United States strongly had opposed the Islamic republic‘s involvement.

Speaking in Helsinki on Wednesday, U.S. Secretary of State Hillary Clinton said she had been in regular contact with Annan over his transition plan, without saying what it contained.

“We think it embodies the principles needed for any political transition in Syria that could lead to a peaceful, democratic and representative outcome reflecting the will of the Syrian people,” she added.

U.S. officials had warned that Clinton could stay away from the Geneva meeting if transition from Assad’s rule was not squarely on the agenda, despite Russian opposition to regime change.

Clinton is to meet Russian Foreign Minister Sergei Lavrov in Saint Petersburg on Friday for talks expected to be dominated by the Syria crisis.

Saturday‘s meeting in Geneva has taken on huge urgency as Annan’s original six-point peace plan has stalled in the face of surging violence.

Of the more than 15,804 people killed since the uprising broke out in March last year, nearly 4,700 have lost their lives since the ceasefire brokered by Annan was supposed to take effect on April 12, according to figures from the Syrian Observatory for Human Rights.

U.N. military observers, who were deployed to oversee the ceasefire, suspended their operations on June 16 in the face of the mounting violence, and the week to Tuesday was the bloodiest of the conflict so far with 916 dead, according to the Observatory‘s figures.

Of the 149 people killed on Wednesday, 77 were civilians -- 14 of them children -- 57 were soldiers and 15 were rebel fighters, the Observatory said.

The rebel Free Syrian Army has exacted a growing toll on the security forces since announcing it would no longer respect the cease-fire in the face of persistent bombardments and assaults on its strongholds.

Among the civilian dead on Wednesday were seven staff of a pro-government satellite television channel killed in an assault that drew angry condemnation of the rebels from Damascus and criticism from Western governments and international human rights watchdogs.

“The terrorist groups stormed the offices of Al-Ikhbariya, planted explosives in the studios and blew them up along with the equipment,” Information Minister Omran al-Zohbi said from the scene.

The attack on the Al-Ikhbariya headquarters outside Damascus was the first of the uprising against the pro-government media.

White House spokesman Jay Carney said: “We condemn all acts of violence including those targeting pro-regime elements.”

Amnesty International’s Middle East and North Africa deputy director Ann Harrison said: “Even a media organization engaged in propaganda is still a civilian object, so it and those working for it must never be deliberately targeted.”