The US State Department in March approved the sale of the Tomahawks, which have a range of 1,500 kms (932 miles) but did not indicate at the time that a contract had been signed or talks had concluded. The ship-launched version of the missiles, manufactured by RTX Corp, will be deployed on the Royal Australian Navy's Hobart-class destroyers, he said. Australia says it needs to upgrade its defence forces as China is undertaking the biggest military build-up since the end of World War Two.