<br/>South Korea and the US are planning joint military exercises in what the Pentagon says is a message of deterrence to North Korea. US Secretary of State Hillary Clinton and Defence Secretary Robert Gates will visit Seoul next week to discuss the exercises, officials said.<br/><br/>Tensions between the two Koreas are high following the sinking of a South Korean warship earlier this year. An international inquiry blamed North Korea, but Pyongyang has denied it.<br/><br/>Pentagon spokesman Geoff Morrell said Mrs Clinton and Mr Gates would discuss and likely approve combined naval and air exercises in the Sea of Japan and the Yellow Sea.