Yemen's rival political parties were divided on Sunday over a stalled Gulf-brokered power transfer deal which a senior Saudi official said President Ali Abdullah Saleh's deputy will sign within a week.
The stalemate came on a day when security forces killed at least 12 people and wounded 500 more when they fired on an anti-Saleh march in the capital.
"To end the crisis we must agree with the opposition on a mechanism for implementing the Gulf initiative," a spokesman for Saleh's ruling General People's Congress (GPC) party, Tariq al-Shami, told AFP.
"This is why dialogue is necessary" with the opposition, which is demanding that Saleh sign the deal before any discussion on ways to implement it, Shami said.
"Dialogue before transfer of power is out of the question," said key opposition leader Sultan al-Atwani.
Last week Saleh, who has been absent from Yemen for more than three months, authorised Vice President Abdrabuh Mansur Hadi to negotiate a power transfer with the opposition.
The so-called Gulf Initiative was proposed by the six-nation Gulf Cooperation Council (GCC) and sets the path for a peaceful transition of power.
The presidential decree gave Hadi "the necessary constitutional authority" to endorse the plan and to negotiate a power transfer mechanism with the opposition.
"This decision is an attempt to avoid the initiative," charged Atwani.
A high-level Saudi official told AFP on Saturday that Hadi will sign the initiative "within a week" after the United States on Thursday said that this is what it had "hoped" for.
Saleh, who has ruled Yemen since 1978, has been recovering in Saudi Arabia from a June 3 attack on his presidential compound, but has refused to hand power to his deputy or sign the Gulf Initiative.
His refusal has angered the plan's Gulf sponsors who, along with many in the international community, fear that a total meltdown of political order in Yemen could pave the way for Al-Qaeda-linked militants to overrun the country.
The GCC plan, proposed last spring, calls on Saleh to step down as president and hand over all constitutional authorities to Hadi. In return, Saleh would receive amnesty from prosecution for himself and his family.
A UN roadmap, drawn up in two weeks of talks in July in Yemen between the opposition and leading GPC figures and chaired by UN envoy Jamal Benomar, also stipulates that Saleh transfer power to Hadi.
Whereas the Gulf plan stipulates a one-month interim period ending with Saleh's resignation, the UN roadmap provides for an extended period of up to six months.
"All ideas from the UN or other parties must be discussed in order to reach an agreement on the mechanism and set a timetable for implementing the initiative," Shami said.
However, for the opposition, such dialogue is a waste of time.
"We do not want to waste any more time," said Atwani as the revolt has entered its ninth month amid political turmoil that is taking an already impoverished Yemen to the brink of total chaos.
On Sunday, security forces fired on anti-regime demonstrators in Sanaa, killing 12 and wounding 500 others, a medic said.
The shooting happened as tens of thousands of protesters left Change Square, where they have camped since February, and marched towards the city centre, witnesses said.
Water cannons and tear gas were also used, they added.
Huge demonstrations also erupted in cities south of Sanaa -- Taez, Yemen's second-largest city, Ibb, and Dhammar -- and in Saada in the north, to denounce Sunday's violence.
A Western diplomat in Sanaa, speaking to AFP on condition of anonymity, said "the signing of the (GCC) initiative is the key to solving Yemen's political, economic and security problems."