The move comes as global oil prices tumbled to a 17-year low, while gold, platinum and silver shed more than over 3%.

ICBC said it will widen the spread when market sees tight liquidity and big fluctuation, in order to reduce market risk.

The bank also warned of speculation and said that it will suspend accounts if it finds any irregular trading movement.

(Reporting by Muyu Xu, Leng Cheng and Beijing Newsroom, editing by Louise Heavens)