Updated

The White House says Kofi Annan's resignation as United Nations envoy to Syria highlights the failure of Russia and China to support action against Syrian President Bashar Assad.

White House press secretary Jay Carney says the U.S. is grateful for Annan's willingness to lead efforts to seek a resolution to the ongoing violence in Syria. But he says the Syrian government was never willing to embrace Annan's plan, which included a cease-fire and allowing international monitors to operate in the county.

Annan announced his resignation Thursday.

Carney says the U.S. will continue working with international partners to halt the violence. But he says the U.S. continues to oppose sending weapons to rebel forces in Syria.