Gulf, U.S. and EU diplomats are trying to resurrect the Gulf Arab deal, which would see Saleh resign a month after signing, as violence rises in the impoverished Arabian Peninsula state, home to one of al Qaeda's most aggressive regional wings.
Modifications proposed by the ruling party, passed on to the opposition by diplomats, would let the ruling party appoint a unity government for the transition period until elections and would also change which opposition representative would sign the deal, the opposition leader said.
"The opposition is now holding another meeting in the next few hours to discuss these ideas and respond to them, but it may stick to the principle that the Gulf initiative cannot be amended," an opposition leader told Reuters.
He indicated that the opposition's main objections were not with the changes being proposed but with setting a precedent for modifying the original deal.
Abdullatif al-Zayani, the secretary general of the Gulf Cooperation Council (GCC), has been in capital Sanaa since Saturday trying to revive the GCC-brokered deal that Qatar, one of its six members, backed out of citing stalling and "lack of wisdom".
Saleh, a shrewd political survivor who has outlasted previous opponents' attempts to challenge his power, indicated in April he would sign the Gulf deal, but refused to put his name to it in the final hours. He said at the time he would only sign in his capacity as ruling party leader, not as president.
He and his party have now agreed he would sign as president of both the party and the country.
In the southern port city of Aden, gunmen in civilian clothes fired into the air at a protest camp early Tuesday morning, protesters said, in an apparent attempt to scare demonstrators out of the area where they have camped out for months to demand Saleh's immediate ouster.
Residents and medics said several were hurt but no one was killed. Fleeing protesters, some of whom hurled stones at their attackers, quickly returned to their camp after the clashes.
Elsewhere in the south, suspected Islamist militants shot dead two soldiers and a civil servant as they drove up in a lorry to a security checkpoint in the southern city of Mukalla, a local official said. A fourth person was wounded.
The United States and neighbouring oil giant Saudi Arabia, both targets of foiled attacks from al Qaeda's Yemen wing, have been keen to see an end to Yemen's political stalemate out of concern that continued chaos could give the militant group more room to operate freely.
Protesters, frustrated that three months of protests have failed to dislodge Saleh, say they will step up their campaign by marching on government buildings, a move which brought new bloodshed last week as security forces fired to stop them.
Aden residents on Tuesday said their city was almost completely shut down -- this time, not by protesters closing government buildings but by army roadblocks posted around the city to prevent a march on the presidential palace.
Protest leaders had called for marches on presidential palaces in several Yemeni cities but on Wednesday sent messages on Facebook cancelling the plan.