UN Secretary General Ban Ki-moon said talks on the Syria crisis had unacceptably been taken "hostage" by the question of President Bashar al-Assad's future, in an interview with Spanish newspapers published Saturday.
"It is totally unfair and unreasonable that the fate of one person takes the whole political negotiation process hostage. It is unacceptable," he said, referring to Assad.
"The future of Assad must be decided by the Syrian people," he said in the interview, according to a translation of his comments in the Spanish daily El Mundo.
Three other Spanish newspapers participated in the interview.
His comments came after diplomats from 17 countries, as well as the United Nations and the European Union (EU), sought to narrow their differences over the four-year-old Syria crisis during a meeting in Vienna on Friday. The Syrian regime and the opposition were not represented.
But regime allies Russia -- which has waged a month of intense air strikes against Syrian rebels -- and Iran are resisting Western and Saudi pressure to force Assad from power.
"The Syrian government insists that President Assad takes part (in any transitional government)" but others, especially Western countries, say "there is no place for him," said Ban.
"But because of that we have lost three years, there have been more than 250,000 dead, more than 13 million displaced within Syria... more than 50 percent of hospitals, schools and infrastructure have been destroyed. There's no time to lose," said Ban.
The UN Office for the Coordination of Humanitarian Affairs (OCHA) says on its website that 6.5 million people in Syria have been internally displaced, 4.2 million have fled the country and 13.5 million are in need of humanitarian assistance.
The United States on Friday announced its first sustained deployment of ground troops to Syria to help the anti-jihadist fight.
The decision to send a small special forces team marks an escalation in Washington's efforts to defeat the Islamic State (ISIS) jihadist group, which has seized Syrian territory despite more than a year of US-led air strikes.