The UN special envoy for Syria has temporarily withdrawn a proposal to form a consultative mechanism on the Syrian constitution, Al Jazeera has learned.

Staffan de Mistura had presented the proposal during the ongoing sixth round of Syria talks that began in Geneva on Tuesday.

He subsequently withdrew the proposal, and it is now on hold awaiting final feedback from the opposition, Issam Rayes, a spokesperson for the High Negotiations Committee (HNC) and a rebel alliance known as the Southern Front in Syria, told Al Jazeera by phone from the Swiss city on Thursday.

The original proposal recommended that de Mistura's office, along with legal experts nominated by the opposition and the Syrian government, oversee all legal issues during a transitional phase in the country.

The Syrian opposition delegation objected to the proposal on Wednesday and demanded that changes be made.

In a statement, the HNC said it had a number of concerns regarding the proposal.

It requested clarification on a number of points, including the nature of the authority that the special envoy's office would have over the country during the transitional phase.

The HNC also requested clarification on how the proposal intended to ensure the cooperation of the Syrian government and the active participation of the Syrian people in the process.

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"We [the opposition] submitted legal inquiries after discussing the proposal with legal experts. We will discuss this in the next meeting today," the HNC's Rayes told Al Jazeera.

Additionally, the HNC requested clarity on how the countries or legal experts who would take part in shaping Syria's legal matters during the transitional phase would be selected.

The present round of Syria negotiations is expected to focus on four separate "baskets": Governance, a new constitution, elections and combating "terrorism" in the country.

Political solution

George Sabra, another spokesperson for the opposition delegation, said on Wednesday that the Syrian opposition was in Geneva to follow up on a political solution in Syria.

"The only people affected by any delay [in finding a political solution] are the Syrian people who are waiting for us to come up with a real and final decision to end the fighting," he said.

"We will not allow another criminal or murderer to make it to the ruling chair. We are here to open a door to a new Syria, a free Syria made up of people from different sects, cultures, political views and religious backgrounds."

Syria's official news agency SANA reported on Thursday that the Syrian government delegation, headed by the diplomat Bashar al-Jaafari, met de Mistura in Geneva.

Al Jazeera's Mohammed Jamjoom, reporting from Geneva, said not a lot has been achieved in the latest round, with the US appearing not to have a clear stance yet.

"There were a lot of promises going into this round of talks, but at this point all that is being discussed are technicality and technical issues," he said.

"A bigger issue hovering over these talks is what exactly is US doing here and what is its stance and policy on Syria.

"If the US is not really engaged in this process, there is a sense that this process is eventually going to fail."

During the fifth round of the Geneva talks, which was held in March, governance, political transition, the constitution and elections and counterterrorism were discussed at the request of the Syrian government.

Deadlock remains over some issues, notably the fate of President Bashar al-Assad, with the opposition insisting on Assad's departure in any political transition, and the Syrian government dismissing the demand as unacceptable.

A deal on de-escalation zones in Syria came into effect in the Astana talks on May 6 is one of the many efforts to reduce violence in the country.

The deal, which was signed by Russia, Turkey and Iran, called for a cessation of hostilities between rebel groups and forces fighting on behalf of the Syrian government in four de-escalation zones located mainly in opposition-held areas of the country.

The four zones cover areas in the provinces of Damascus, Idlib, Latakia, Aleppo, Homs, Hama, Deraa and Quneitra.

The UK-based Syrian Observatory for Human Rights (SOHR) said on Wednesday that a 94 percent decrease in civilian casualties in the de-escalation zones has been recorded since the agreement came into force.

At least eight people were killed in the four zones since May 6, the SOHR said.

As the Syrian conflict enters its seventh year, more than 465,000 people have been killed in the fighting, more than one million injured and more than 12 million - half of the country's pre-war population - displaced from their homes.

With additional reporting by Diana AlRifai: @D_R_23