BANDAR SERI BEGAWAN -- U.S. Secretary of State John Kerry says the U.S. thinks China could have "made a difference" in the case of National Security Agency leaker Edward Snowden if it had returned him to America to face charges.

But Kerry says the U.S.-China relationship is bigger than one incident and that the two countries co-operate on numerous issues, including North Korea.

Kerry spoke Monday at a Southeast Asia conference in Brunei.

Snowden's efforts to evade U.S. authorities -- taking him from a hotel hideout in Hong Kong to an airport transit zone in Moscow -- have undercut U.S. efforts to strengthen ties with China and threaten to worsen tension with Russia just as President Barack Obama seeks Moscow's co-operation on Syria. Kerry is to meet Tuesday with Russian Foreign Minister Sergey Lavrov.