By Jack Kim SEOUL (Reuters) – South Korean and U.S. troops have conducted joint combat firing drills near the border with North Korea involving heavy weapons, as Pyongyang lambasted the allies for dangerous moves pushing the region to the brink of “an inferno of nuclear war.” The exercise by a South Korean Army mechanised infantry brigade and U.S. Army armoured Stryker brigade was to test and enhance combat readiness simulating enemy aggression, South Korea said in a statement on Thursday. The drills took place over a week starting on Dec. 29 and ended on Thursday, the South Korean Army said. …