North Korea may already have 20 nuclear warheads - double as many as previously thought , Chinese nuclear experts have warned . The pariah state may also have the capability to produce enough weapons-grade uranium to double its arsenal by next year , The Wall Street Journal has reported . Chinese estimates of Pyongyang 's nuclear production , relayed to US nuclear specialists , exceed most previous US forecasts of between 10 to 16 bombs , said the report , which cited people briefed on the matter . Scroll down for video . A North Korean vehicle carrying a missile passes by during a mass military parade in Pyongyang 's Kim Il Sung Square . The pariah state may have as many as 20 nuclear warheads , it has now been suggested . North Korean leader Kim Jong Un addresses Korean People 's Army pilots in an undated photo released by the state news agency earlier this month . Under the Kim dynasty North Korea has long used nuclear weapons as a bargaining chip in international relations . Experts at the US-Korea Institute at Johns Hopkins University 's School of Advanced International Studies earlier this year presented three scenarios for North Korea 's nuclear capability , predicting its stockpile of weapons could grow to 50 or even 100 within five years . North Korea has conducted three nuclear detonations , the most recent in February 2013 . Asked about the report at a regular press briefing yesterday , China 's Foreign Ministry spokesman Hong Lei said he 'did not have knowledge of the specific situation ' . 'We must persevere with denuclearisation on the Korean peninsula , persevere in safeguarding peace and stability , and persevere in resolving the relevant issue through dialogue , ' Hong said . Earlier this month , US Admiral William Gortney , commander of the US Northern Command and North American Aerospace Defense Command , said the US military believes North Korea has the ability to miniaturise a warhead and mount it on a ballistic missile , although there had been no tests . One such rocket is an intercontinental missile with could theoretically hit California as it is designed to carry a payload of more than 5,000 miles . Kim Jong Un ( centre in black ) posing with his soldiers on top of snow-covered Mount Paektu in North Korea . The country could have as many as 100 warheads within five years , it has been suggested . Stanford University professor Sigfried Hecker was allowed to visit Pyongyang in 2010 and reported seeing a large uranium-enrichment facility . The Journal quoted him as saying : 'Some eight , nine , or 10 years ago , they had the bomb but not much of a nuclear arsenal . ' I had hoped they would n't go in this direction , but that 's what happened in the past five years . 'The more they believe they have a fully functional nuclear arsenal and deterrent , the more difficult it 's going to be to walk them back from that . ' North Korea carried out nuclear tests in 2006 , 2009 and 2013 , and has an extremely active ballistic missile development programme , although expert opinion is split on how much progress it has made , reports Agence France Presse . The Chinese estimate reflects growing concern in Beijing about the nuclear ambitions of its errant ally , and is the latest in a series of expert assessments that suggest Pyongyang is moving faster down the nuclear path than previously thought . Kim Jong Un inspecting the newly built Wonsan Baby Home and Orphanage in a photo released earlier this month . North Korea has conducted three nuclear detonations , the most recent in February 2013 . In 2012 , Pyongyang demonstrated its rocket capabilities by sending a satellite into orbit , but it has yet to conduct a test that would show it had mastered the re-entry technology required for an inter-continental ballistic missile . The other key question is how close the North is to being able to miniaturise a nuclear device that could be fitted on the tip of a missile . In a white paper published in January , the South Korean defence ministry said the North had already taken its miniaturisation technology to a 'significant ' level . Under the Kim dynasty , represented by current leader Kim Jong Un , North Korea has long used nuclear weapons as a bargaining chip in international relations . Last month the country 's ambassador to the UK issued a chilling warning that North Korea would be prepared to use nuclear weapons . In a rare interview , Hyun Hak-bong claimed the secretive state could launch a deadly warhead 'anytime ' .
Pariah state may have 20 warheads not 10 as previous US forecasts held . Stockpile of weapons could grow to 50 or even 100 within February 2013 . US military believes secretive country has ability to miniaturise warhead and mount it on ballistic missile , though there have been no such tests yet .