SEOUL — US and South Korean troops will stage an annual joint exercise next month to improve their combat-readiness, military authorities said Monday amid high cross-border tensions. The allies will hold Ulchi Freedom Guardian, which is largely a computer-simulated exercise, on Aug. 20-31, the Combined Forces Command said in a statement. North Korea has been told of the dates and of the non-provocative nature of the exercise, it said. The drill will involve many of the 28,500 US troops stationed in the South as well as some 3,000 from abroad but there will be no field training, a US military spokesman said. — AFP