U.S. President Barack Obama assured ally Japan on Thursday that Washington was committed to its defense, including of tiny isles at the heart of a row with China, but denied he had drawn any new “red line” and urged peaceful dialogue over the islands. His comments drew a swift response from China, which said the disputed islets were Chinese territory. Obama also urged Japan to take “bold steps” to clinch a two-way trade pact seen as crucial to a broad regional agreement that is a central part of the U.S.