Mumbai, June 24 -- COMEX Copper futures stayed under sustained pressure and approached near $6 per pound, testing their six-week low. A firm US dollar index, which holds well above 101 mark, is pulling metals lower and COMEX Copper is currently trading down 1.55% at $6.05 per pound. The metal has lost around 5% this week. MCX Copper is also down 2.26% at Rs 1272 per kg as a slide under Rs 1300 mark extended. The open interest in the counter edged up today. Meanwhile, Asian shares were mostly steady. China's Shanghai Composite index added 0.11% while Hong Kong's Hang Seng index rose 0.33%. Japan's Nikkei average fell 0.88%. European stocks are mixed though German equities turned lower. German DAX is down more than 1%. US markets stayed under...