Russia and China blocked a proposed consensus statement for the East Asia Summit drafted by Southeast Asian countries, mainly over objections to language on the contested South China Sea, a U.S. official said Saturday.

A draft statement arrived at by consensus by the 10-nation Association of Southeast Asian Nations was put to the 18-nation East Asia Summit meeting in Laos on Thursday evening, the official said.

“ASEAN presented this final draft and said that, essentially, this was a take-it-or-leave-it draft,” the official said on condition of anonymity.