Expectations are low that the new United Nations envoy to Syria will have any more success at settling the conflict than his predecessor.
Lakhdar Brahimi, an Algerian who brokered an accord in Lebanon's civil war in the 1980s, has held meetings at the UN headquarters before taking up the job on Wednesday.
He expects to go to Damascus soon to meet President Bashar al-Assad, but admits to being apprehensive about the responsibility he is taking on.
Previous UN-Arab League envoy Kofi Annan resigned after his peace plan failed to achieve a ceasefire.
"I'm coming into this job with my eyes open, and no illusions," Mr Brahimi told the BBC in New York.
"I know how difficult it is - how nearly impossible. I can't say impossible - (it is) nearly impossible.
Mr Brahimi said he had so far failed to see "any cracks" in the "brick wall" that had defeated Mr Annan: an "intransigent" Syrian government, escalating fighting and paralysis in the UN Security Council.
He said the need for political change in Syria was "fundamental and urgent", but refused to be drawn on whether Mr Assad should step down.
"Change cannot be cosmetic. There will be a new order, but I do not know who will be the people in the order. That's for Syrians to decide."