Hillary Clinton threatened to “ring” China with defensive missiles if Beijing did not rein in North Korea, leaked emails detailing a private speech she made three years ago claim.

The US democratic presidential candidate also blamed the Chinese military for being Pyongyang’s biggest ally, according to the hacked emails, which were revealed by Wikileaks.

The former secretary of state’s comments reflect ongoing frustrations in Washington that China has been failing to use its influence as North Korea’s biggest trading partner and ally to encourage the regime to cease its nuclear weapons programme.

The threat of an increased US military profile in the region would cause alarm in China, which expressed anger in July after Seoul’s decision to deploy a US anti-missile defence system to counter threats from North Korea.

Pyongyang conducted its fifth nuclear test earlier this year, and Beijing claims its influence is limited with the country's leaders.

“You know, we all have told the Chinese if they (North Korea) continue to develop this missile program and they get an ICBM (Intercontinental Ballistic Missile) that has the capacity to carry a small nuclear weapon on it, which is what they’re aiming to do, we cannot abide that,” Mrs Clinton told a Goldman Sachs conference in June 2013, according to the leaked data.