by Giles HEWITT SEOUL, South Korea (AFP) — Tens of thousands of South Korean and US troops began a military exercise simulating an all-out North Korean attack Monday, as Pyongyang threatened a pre-emptive strike on forces participating in the drill. The two-week annual Ulchi Freedom exercise is largely computer-simulated, but still involves 50,000 Korean and 30,000 US soldiers. The drill always triggers a spike in tensions on the divided Korean peninsula, and this year it […]