Hopes faded Monday for a quick win at peace talks between Syria’s warring factions after the Syrian government declined to authorize a convoy of food to enter a besieged neighborhood in the center of the city of Homs under the terms of an agreement brokered by the United Nations.

There was no sign, either, that a promise to allow women and children to leave was moving forward, calling into question whether progress would be possible on the far more momentous issues that will have to be discussed if the conference is to end Syria’s brutal civil war.

U.N. envoy Lakhdar Brahimi seemed dejected as he briefed reporters on the third day of the peace talks, which have so far succeeded only in exposing the vast gulf dividing the government and opposition delegations.

“The discussions haven’t produced much, unfortunately,” he said.

“We never expected a miracle,” he added. “There are no miracles here, but we will continue and see if progress can be made and when.”

The big story

THE TALKS: On Friday, representatives of Syria's government and the opposition met for the first time as part of the Geneva II talks. Talks have continued between the two sides, which disagree on the fundamental issue of whether President Bashar al-Assad could have a place in a transitional government.

THE CONFLICT: More than 120,000 people have been killed and 2 million displaced in a conflict that began in March 2011 as largely peaceful protests against Assad. Fractious opposition groups are battling fighters loyal to Assad as well as those linked to al-Qaeda, part of the Islamic State of Iraq and Syria.

Timeline: Unrest in Syria

Almost three years after the first anti-government protests, conflict in Syria rages on. See the major events in the country's tumultuous uprising.

At Monday’s session, the contentious question of what the warring factions hope to achieve at the conference was broached for the first time, with Brahimi asking the two sides to present their visions for a future Syria.

The government submitted a blueprint for ways to salvage the current Syrian state, fight terrorism and restore territories lost to rebel control; the opposition immediately rejected it.

“We didn’t even look at it,” said Munzer Akbik, an adviser to Syrian Opposition Coalition President Ahmad al-Jarba.

The opposition said it presented a copy of the Geneva I communique, which spells out the conditions under which the conference is being held, as the basis of its proposal. The communique, agreed to by the United States and Russia in June 2012, lays out a framework for resolving the Syria crisis that includes humanitarian measures, a cease-fire and the creation of a transitional executive body that would take power away from President Bashar al-Assad’s regime.

Brahimi and other diplomats have repeatedly warned that the talks could last months if they are to succeed in bridging the differences between those seeking the overthrow of Assad and those representing his government.

The failure to secure an agreement on humanitarian aid to Homs, intended to be an early goodwill gesture, is raising questions about whether Syria’s government will be prepared to compromise on tougher political issues. Residents of the Old City of Homs, where people are in danger of starving after nearly 18 months under siege, said government shelling of the neighborhood intensified after the discussions began on a cease-fire to let aid in.

“We haven’t seen any goodwill yet,” opposition spokesman Louay Safi said. “So we ask whether the regime is serious about a political transition.”

U.S. officials monitoring the Geneva talks also expressed frustration with the lack of progress on access for the convoy, comprising 12 trucks carrying aid and medical supplies. The plan had been discussed before the talks, in the hope of being able to demonstrate early progress, and the convoy has been ready to move for days, diplomats said.

The government’s offer to allow women and children to leave was part of a broader package of proposed measures and is not sufficient, said Edgar Vasquez, a State Department spokesman.

“Civilians must be allowed to come and go freely, and the people of Homs must not be forced to leave their homes and split up their families before receiving much-needed food and other aid,” he said. The tactic echoes a “kneel or starve” campaign, in which troops surround rebel-held communities and deny them access to food and medicine to force them to submit, Vasquez added.

Activists issued a statement saying a single convoy of aid would not be enough to address the dire conditions in the besieged area, where there is a chronic lack of food, as well as medical care for people injured in the shelling. They called for a comprehensive cease-fire that would allow anyone who wanted to leave to do so safely.

But the government has insisted that no men can leave until a list is submitted to authorities of the names of all male residents in the area, raising fears that they would be targeted for arrest.

Brahimi has said this first round of talks will continue until the end of the week, then there will be a break of about a week for the two sides to consult. Negotiations around the aid delivery will continue through the week, and it could still materialize in the coming days, he said.

Bringing the two sides together at all was an achievement, Brahimi said, but he cautioned that it was “only one little step forward.”

“Whatever gain we have made is reversible,” he said.

Ahmed Ramadan contributed to this story from Beirut.