The Syrian government has ruled out discussion of the presidency at peace talks, calling President Bashar al-Assad a "red line" and saying the opposition was deluded if it thought it could take power in Geneva.
Foreign Minister Walid al-Moualem on Saturday confirmed his government's participation in UN-led talks due to begin on Monday but said they would fail if the opposition had "delusions that they will take power in Geneva that they failed to take in battle".
The government delegation would reject any attempt to include presidential elections on the agenda, he said.
"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 during a televised news conference in Damascus.
"I advise them that if this is their thinking, they shouldn't come to the talks.
"They must abandon these delusions."
Moualem said the government delegation would travel to Geneva on Sunday but would return to Damascus within 24 hours if the other side did not show up.
The Syrian government's understanding of "political transition" was from the existing constitution to a new one, and from the existing government to a new one with participation from the other side, he said.
The Syrian opposition wants the talks to focus on the establishment of a transitional governing body with full executive powers, and has rejected the idea of joining an expanded Syrian government.
In response to Moualem's comments, the main opposition council accused Damascus of halting the talks before they had started.
"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, told Al Arabiya Al Hadath TV.
"Moualem is stopping Geneva before it starts."
The foreign minister also said the government was committed to a "cessation of hostilities" agreement brokered by the United States and Russia that has reduced the violence in western Syria since it came into effect two weeks ago.
He criticised UN envoy Staffan de Mistura, saying neither he or anyone else had the right to talk about presidential elections in Syria and demanding "neutrality and objectivity" on his part. He also rejected the idea of a federal solution to the war.