North Korea raised the stakes by firing a medium-range ballistic missile into the sea off its east coast on Wednesday, the eve of a much-anticipated U.S.-China summit.

The missile, which was launched from a port city known for its submarines, flew for nine minutes before splashing into the sea about 40 miles away, U.S. and South Korean officials said.

The U.S. Pacific Command said initial assessments indicated it was a KN-15 medium-range missile. But a senior U.S. defense official said later that it was an extended-range Scud missile, which suffered an in-flight failure. […]