London ( CNN ) -- Iran has been carrying out covert tests of missiles capable of delivering a nuclear payload , UK Foreign Secretary William Hague said Wednesday , in contravention of a U.N. resolution . It has also said it wants to enrich uranium to `` levels far greater than is needed for peaceful nuclear energy , '' Hague said . Iran 's development of missile and nuclear fuel technology has led to U.N. sanctions and accusations from the United States that the clerical regime is trying to develop nuclear weapons . Iran says it has a right to peaceful nuclear technology , but the International Atomic Energy Agency ( IAEA ) says it can not verify whether Tehran 's nuclear program remains entirely peaceful . Iran has not yet responded to Hague 's claims . His comments in the House of Commons come a day after Iranian news agencies reported that the country 's military had successfully test-fired 14 missiles during military drills , as part of a week of war games . Tehran also unveiled several ballistic missile silos Monday , and Wednesday demonstrated what was described by the semi-official Fars news agency as a new Iranian-made long-range radar system capable of monitoring low-altitude satellites . Speaking in London , Hague said : `` Iran has also been carrying out covert ballistic missile tests and rocket launches , including testing missiles capable of delivering a nuclear payload in contravention of U.N. resolution 1929 , and it has announced that it intends to triple its capacity to produce 20 % enriched uranium . '' The UK foreign secretary promised to `` maintain and continue to increase pressure on Iran to negotiate an agreement on their nuclear programme , building on the strengthening of sanctions , '' announced earlier this month . Enriched uranium can be used for civilian nuclear purposes , but also to make atomic weapons . The IAEA raised concerns in February that Iran was not engaging with the agency on claims that it was developing a nuclear payload for its missiles . The IAEA report discussed possible nuclear activities tied to Iran 's military `` including activities related to the development of a nuclear payload for a missile . '' The United States imposed new sanctions on Iran last week , targeting the country 's national airline , Iran Air , other companies , and international business executives accused of illicitly building up Tehran 's military . Iran condemned those sanctions in a letter to the United Nations , saying the international body had a responsibility to look out for `` nations who are merely endeavoring to attain their legitimate and undeniable rights under international law . '' The United Nations passed a fourth round of sanctions against Iran in June 2010 , aimed at pressuring it to suspend its nuclear program .
Foreign secretary says Iran also wants to enrich uranium beyond peaceful levels . His remarks come a day after Iran test-fired 14 missiles . Tests are in contravention of a U.N. resolution , Hague says . The United States imposed new sanctions against Iran last week .