The Liberal backbencher and former army commander Andrew Nikolic, Australian politician and MP has warned that Iran presents a potentially worse threat than Islamic State (Isis), one that may require an urgent military response. Nilolic said that as Australia joined the international coalition to fight Isis, "the time for action on Iran is now much closer than it has ever been".

Israel said on Wednesday that Iran has used its Parchin military base as the site for secret tests of technology that could be used only for detonating a nuclear weapon. The Jewish state has been a severe critic of six big powers' negotiations with Iran on curbing its nuclear energy programme, suspecting Tehran is only trying to buy time to master sensitive nuclear know-how and would evade the terms of any final deal.

Tehran could outsource the completion of a bomb to its longtime ally, North Korea. As a venue for secretly completing and testing a nuclear bomb, North Korea would be ideal. North Korea is the only country known to have tested any nuclear bombs since India and Pakistan both performed underground tests in 1998. Despite wide condemnation, it has gotten away with three nuclear tests, in 2006, 2009 and 2013. Pyongyang threatened to carry out a fourth test in March, which it said would take an unspecified "new form."

The Iranian government this week published its first detailed study of how long it estimates it would take its scientists and engineers to assemble a nuclear weapon, saying that with its current infrastructure, "the required time span is in years.: Iran described the estimate as entirely hypothetical, and it was clearly intended to allay fears that Iran has the ability to race for a bomb.