The main Syria opposition coalition, the so-called High Negotiations Committee (HNC), says it will not attend a planned meeting with the United Nations special envoy for Syria.

“There is no meeting with (Staffan) de Mistura,” planned for Tuesday afternoon, HNC member Farah Atassi told reporters outside of the UN headquarters in the Swiss city of Geneva, where the Syria peace talks are going on.

“We presented the demands that we wanted to demand. At this moment, there is no reason to repeat ourselves with de Mistura,” she added.

The gathering was to be the opposition delegation’s second meeting with the Swedish-Italian diplomat as part of the UN-brokered peace Geneva negotiations aimed at finding a political solution to the conflict in Syria.

United Nations spokeswoman Khawla Mattar also confirmed that there would be “no other meetings today” in Geneva with de Mistura.

Earlier in the day, the UN envoy held talks with the Damascus government delegation. The meeting came one day after de Mistura announced the beginning of peace talks proper in the Swiss city of Geneva.

Following the event, however, Syria’s ambassador to the UN, Bashar al-Jaafari, who has represented the Syrian government in the peace talks, said the negotiations are still in a preliminary phase and called the opposition “not serious”.

The ongoing Syria talks are to be held in an 18-month timetable under a resolution unanimously approved by the UN Security Council.

Adopted on December 18, 2015, the resolution calls for a nationwide ceasefire in Syria and the formation of a “credible, inclusive and non-sectarian” government within six months as well as UN-supervised “free and fair elections” within 18 months.

Some 17 nations – including the United States, Russia, Saudi Arabia, Turkey and Iran – held several rounds of talks last year in the broadest international push to end the crisis in Syria.

The foreign-sponsored Syrian conflict, which began in March 2011, has reportedly claimed the lives of more than 260,000 people, and displaced almost eight million others.