China is expected to at least double the number of its nuclear warheads over the next 10 years – from an estimated figure in the low 200s it has now – and is nearing the ability to launch nuclear attacks by land, air and sea, a capacity known as a triad, the United States has revealed. The Pentagon, presenting a report to Congress while the house debates the pending $700bn defence authorisation bill amid rising tensions between the two countries, said the growth projection was based on factors including Beijing having enough material to double its nuclear weapons stockpile without new fissile material production.