Metal stocks nosedived in the domestic stock market as metal prices fell in global markets in response to North Korea tensions and S&P's downgrade of China's credit rating.

NMDC, Vedanta, and Hindalco plunged up to 3 per cent. Steep fall in the share prices of JSW Steel (down 6.07 per cent), Nalco (-5.52 per cent), Jindal Steel (-5.08 per cent), and Tata Steel (-4.05 per cent) dragged Nifty Metal index over 3 per cent lower to 3,366-level.

The Nifty Metal index was trading down at 3,410.60, down 2.33 per cent at 12 noon.

S&P has lowered China's sovereign credit rating one notch to A+ from AA-, putting it in line with those of Moody's and Fitch, citing economic and financial risks.

North Korea could consider testing a hydrogen bomb over the Pacific Ocean in retaliation to Donald Trump's threats to destroy the country, Pyongyang's Foreign Minister had said last week.

The Sensex plunged 350 points and the Nifty touched 9,851-mark in opening trade on persistent concerns about US-North Korea tug-of-war amid foreign capital outflow.