The main Syrian opposition council accused the Syrian regime on Saturday of halting peace talks before they had started after the regime's Foreign Minister Walid al Moualem rejected the idea of a transition of power without Bashar al Assad.
"I believe he is putting the nails in the coffin of Geneva, this is clear," Monzer Makhous, a member of the opposition High Negotiations Committee (HNC), told Al Arabiya Al Hadath TV in response to Moualem's remarks.
"Moualem is stopping Geneva before it starts," Makhous added.
Moualem said during a televised news conference in Damascus on Saturday that Assad is a "red line" as it confirmed its participation in UN-led peace talks next week.
"We will not talk to anyone who talks about the position of the presidency. Bashar is a red line, the property of the Syrian people," Moualem said.
"I advise them that if this is their thinking, they shouldn't come to the talks."
Last year world powers agreed on a plan and called for six months of negotiations followed by a transitional government, a new constitution and elections within 18 months.
The last round of UN-sponsored talks collapsed in February after the Syrian regime began a fierce Russian-backed offensive around Aleppo targeting moderate rebels.
Opposition wants talks on transitional governing body
The HNC has also confirmed its attendance and praised an agenda outlined by UN special envoy to Syria Staffan de Mistura which focuses on governance, a new constitution and elections.
The HNC wants to the focus of talks to be on a transitional governing body with full executive powers as outlined in a 2012 Geneva communique drawn up in an early bid to end the conflict.
A UN Security Council resolution approved in December called for the establishment of "credible, inclusive, and non-sectarian governance," a new constitution and free and fair elections within 18 months.
HNC chief negotiator Mohamad Alloush was cited as saying the opposition had come to Geneva to negotiate a transitional body without Assad in power.