U.S. Secretary of State John Kerry is calling the rocky start to Syrian peace talks "a tough and complicated process."

Kerry spoke to reporters after a bitter clash Wednesday over President Bashar Assad's future threatened to collapse peace talks, even before they had begun, with the aim of carving a path out of Syria's civil war.

Kerry noted that the purpose of conference was to begin the creation of transitional government and that "every entity here today with one exception talked about that."

The resolution of the talks, he said, "cannot be about one man, or one family, insisting on clinging to power."

Syrian delegates responded to talks of Assad leaving office bluntly, saying that "there will be no transfer of power and Bashar Assad is staying."