UNITED NATIONS, July 25 (Xinhua) -- The Security Council on Wednesday offered its backing to UN special envoy for the Syria crisis, Staffan de Mistura, at the upcoming intra-Syria negotiations in Russia's Sochi, said the council president.

"Members of the Security Council have reiterated their full support for his leadership to facilitate a viable and durable solution to the Syrian conflict," Swedish ambassador to the United Nations Olof Skoog, whose country holds the council presidency for the month of July, told reporters.

The council members reaffirmed their strong commitment to the Syrian-led political process facilitated by the United Nations, said Skoog after the Security Council heard a briefing from de Mistura in closed-door consultations.

The members of the Security Council called on Syrian parties to engage "constructively, in good faith and without preconditions" with de Mistura regarding the formation of a constitutional committee, said the Swedish ambassador.

Participants to a previous Sochi meeting within the the framework of the Astana process agreed to establish an inclusive constitutional committee, which will draft a new constitution for the war-torn country.

The participants to the Sochi meeting in January 2018, including the three guarantors of the Astana process -- Russia, Turkey and Iran -- agreed to put de Mistura in charge of the formation of such a committee within the framework of the UN-led Geneva process.

"He will now take the strong commitment of the Security Council members with him to Sochi, where this will be discussed and he will take the lead proactively to get the constitutional committee going," said Skoog.

Security Council members also emphasized the need for safe, rapid and unhindered humanitarian access in Syria and full respect for international humanitarian law, he said.

At Wednesday's consultations, Sweden and several other council members mentioned the fact that the ongoing military offensive of the Syrian government does not create the best environment for a credible political process, said Skoog.

Speaking to reporters before the start of Wednesday's consultations, Skoog warned against "an inflated belief" that stability can be established in Syria through a military victory.

"The political process is going to be flawed and difficult to get started until we get a true cessation of hostilities on the ground," he said.