WASHINGTON (AP) -- The White House says that Syria's future cannot include President Bashar Assad.

White House spokesman Jay Carney says the U.S. views Syria's future as being a post-Assad future. But he says it's up to the Syrian opposition to decide which elements of Assad's regime could be included in a transitional government.

Carney was asked to clarify the U.S. position a day after Secretary of State John Kerry said the U.S. and Russia would convene a conference soon to seek peace talks between the Syrian government and the opposition. Obama has long said Assad must leave office. But Kerry said Tuesday it was up to the Syrian people whether he should leave.

The Obama administration also announced $100 million in new humanitarian aid Wednesday to the opposition.