<sod >In a further sign of the increased tensions, the US and South Korea conducted an offensive ballistic missile drill early on Wednesday, officials said.< eod>< sod > "Our commitment to the defence of our allies, the Republic of Korea and Japan, in the face of these threats, remains ironclad."Â  In a further sign of the increased tensions, the US and South Korea conducted an offensive ballistic missile drill early on Wednesday, defying a call for a freeze on such activity by Russia and China.< eod>