For U.S., Asian role key on North Korea

WASHINGTON (Reuters) - The United States expects backing from China, South Korea and Japan in a push for new sanctions after North Korea tested a nuclear weapon, but it is unclear whether the three key Asian states will go as far on penalties as Washington might think necessary. 

"If there is no reaction by the international community, this could mean end to the nuclear Non-proliferation Treaty and it would set a bad precedent for other countries, like Iran," a senior Republican U.S. congressional aide said, referring to the current stand-off between major powers and Tehran over Iran's nuclear program.