BEIRUT (Reuters) - Syria’s main opposition body said on Wednesday it would be “unacceptable” for the United Nations to choose opposition delegates to the next round of peace talks in Geneva planned for this month.

Slideshow ( 2 images )

The armed opposition separately stated that no outsiders could choose Syrian representatives to talks, and that it would not accept invitations to negotiations which did not lead to “transition of power to a transitional governing body.”

The next round of UN-based peace talks on Syria have been scheduled for Feb. 20, diplomats said on Tuesday.

The UN envoy for Syria, Staffan de Mistura, has said the UN would choose the opposition’s representatives if they cannot agree on their delegation, “in order to make sure that it can be as inclusive as possible.”

“Mr. de Mistura’s talk of his intentions to form the opposition delegation himself is unacceptable,” the Saudi-backed High Negotiations Committee, the main opposition umbrella group, said on Twitter, citing its spokesman Salim al-Muslit.

“Would de Mistura be able to intervene in forming the regime’s delegation?” asked the HNC, which includes political and armed groups and represented the opposition in peace talks last year.

HNC chief coordinator Riad Hijab said on Twitter: “Selecting the Syrian opposition delegation is not de Mistura’s business.”

The armed opposition echoed the sentiment, saying that it was “no one’s right ... to appoint people to negotiate in the name of the Syrians”, and demanded an apology from de Mistura.

It said there could be no steps towards a political solution to the civil war without full enforcement of a ceasefire.

The Syrian government and rebel groups opposed to President Bashar al-Assad began a nationwide ceasefire in late December, brokered by Moscow and Ankara.

The UN-sponsored talks had been planned to begin in Geneva on Feb. 8 but Russia’s Foreign Minister Sergei Lavrov said last week they had been postponed. Invitations to the talks are due to go out on that day.

De Mistura said on Tuesday he delayed the talks to take advantage of last week’s indirect talks between the Syrian government and opposition in the Kazakh capital of Astana.

They ended with Moscow, Ankara and Tehran agreeing to monitor government and rebel compliance with the shaky ceasefire.