There has been broad international condemnation of North Korea's underground nuclear test carried out earlier today.
Iran responded by saying all the world's nuclear weapons should be destroyed.
"We think we need to come to a point where no country will have any nuclear weapons," Iranian Foreign Ministry spokesman Ramin Mehmanparast told a weekly news conference when asked about the test.
"All weapons of mass destruction and nuclear arms need to be destroyed."
Mr Mehmanparast added that all countries should be able to use nuclear technology for peaceful purposes.
Iran is under UN sanctions over its own nuclear programme, which the US and some of its allies suspect is aimed at developing an atomic weapons capability. Iran denies that charge and says its programme is purely peaceful.
Meanwhile, French president Francois Hollande strongly condemned North Korea's carrying out of a third nuclear test and said it was working with its United Nations Security Council partners on a firm response.
"France demands again that North Korea conform without delay to its international obligations and begin a complete, verifiable and irreversible dismantlement of its nuclear and ballistic programme," Mr Hollande said in a statement.
He said North Korea must refrain from any further action that could increase tensions in the region.
German foreign minister Guido Westerwelle strongly condemned the test and said the international community should consider further sanctions against Pyongyang.
"Foreign Minister Westerwelle strongly condemns the nuclear test in North Korea as another gross violation of UN Security Council resolutions," the foreign ministry said in a statement.
"The international community must respond with a clear stance to this fresh provocation. Further sanctions against the regime in Pyongyang must be considered," it said.
Russian foreign minister Sergei Lavrov, on a trip to South Africa, said North Korea must abandon its nuclear programme and restart talks with the international community, in response to the test.
The isolated state's third nuclear test should not be used to justify more military activity on the Korean peninsula, Mr Lavrov told reporters in Pretoria, the South African capital.
North Korea "should stop its nuclear missile programme because it is violating the non-proliferation treaty", Mr Lavrov said. "I really hope that this step from Pyongyang won't be used as a pretext to expand military activity on the peninsula."
UN secretary-general Ban Ki-moon stated: “It is deplorable that Pyongyang defied the strong and unequivocal call from the international community to refrain from any further provocative measures.”
The North Atlantic Treaty Organisation (Nato) condemned the test, calling it an "irresponsible act" that posed a grave threat to world peace.
North Korea's pursuit of weapons of mass destruction represented continued defiance of the UN Security Council, the North Atlantic Council, made up of Nato ambassadors, said in a statement.
"This irresponsible act, along with the December missile launch, poses a grave threat to international and regional peace, security and stability," it said, urging North Korea to "cease immediately such provocative actions".
The European Union's foreign policy chief Catherine Ashton condemned the test and told Pyongyang to refrain from further provocative actions.
"This nuclear test is a further blatant challenge to the global non-proliferation regime and an outright violation of [North Korea's] international obligations not to produce or test nuclear weapons," Ms Ashton said in a statement.
"We once again urge [North Korea] to abandon its nuclear weapons programme, including its uranium enrichment programme, in a complete, verifiable and irreversible manner," she said.
The nuclear test is a matter of deep concern, India's foreign ministry said, adding such actions violated international commitments and had an adverse impact on peace and stability in the region.
"It is a matter of deep concern that DPRK has acted in violation of its international commitments in this regard," the ministry said, using an abbreviation of North Korea's official name, the Democratic People's Republic of Korea.
"We call upon DPRK to refrain from such actions which adversely impact on peace and stability in the region," the statement said.
Tibor Tóth, executive secretary of the preparatory commission for the Comprehensive Nuclear-Test-Ban Treaty Organisation, said: "It constitutes a clear threat to international peace and security and challenges efforts to strengthen global nuclear disarmament and non-proliferation.
"I am gravely concerned by this action, which deserves universal condemnation.”