Iran’s supreme leader, Ayatollah Ali Khamenei, has defended the country’s missile programme in the face of rising concerns among members of the UN security council. Photograph: Reuters

Ayatollah Ali Khamenei, the supreme leader of Iran, has firmly defended the country’s missile programme in the face of rising concerns among members (...)

Turkey’s president Tayyip Erdogan with his wife Emine arrive in  Washington for this week’s Nuclear Security Summit. Several countries are balking at safeguards promoted by the United States or are building new stockpiles. Photograph: Yuri Gripas/Reuters

As US president Barack Obama gathers world leaders in Washington this week for his last Nuclear Security Summit, tonnes of materials that terrorists c(...)

A security guard walks past the Weatherford booth during the Basra International trade fair for oil and gas in Iraq in 2010. Radioactive material was stolen in November from a storage facility belonging to Weatherford. Photograph: Atef Hassan/Reuters

A “highly dangerous” radioactive material that went missing in Iraq has been found dumped near a petrol station in the southern town of Zubair, enviro(...)

UAE vice president and prime minister, Sheikh Mohammed bin Rashid al-Maktoum with French foreign minister Laurent Fabius during their meeting at his palace in Dubai on Monday. Photograph: Karim Sahib/Getty Images

The European Union will consider this week whether to follow Washington’s lead and impose sanctions on Iran as a response to the country’s ballistic m(...)

US Secretary of State John Kerry is greeted by the US Ambassador to Austria Alexa Wesner as he steps from his plane upon arriving in Vienna on Saturday on what is expected to be “implementation day,” the day the International Atomic Energy Agency (IAEA) verifies that Iran has met all conditions under the nuclear deal. Photograph: Kevin Lamarque/Reuters

International sanctions on Iran will be lifted on Saturday when the United Nations nuclear agency declares Tehran has complied with an agreement to sc(...)

Expectations have been high in Tehran and western capitals over Iran’s reintegration in the global economy, with European businessmen rushing to Tehran to propose deals. Above: a man drives a motorcycle in Tehran.  Photograph: Simon Dawson/Bloomberg via Getty Images

A punitive sanctions regime progressively imposed on Iran over the past decade could begin to lift as early as Monday, if the International Atomic Ene(...)

International Atomic Energy Agency (IAEA) director-general Yukiya Amano addresses a news conference in Vienna, Austria. Photograph: Heinz-Peter Bader/Reuters

The UN nuclear watchdog’s 35-nation board decided on Tuesday to close its investigation into whether Iran once had a secret nuclear weapons programme,(...)

Iran’s Ayatollah Ali Khamenei said Tehran should not give up core elements of its atomic programme until allegations of past military dimensions had been settled. Photograph: Reuters

Supreme Leader Ayatollah Ali Khamenei on Wednesday approved the Iranian government’s nuclear deal with world powers but said Tehran should not give up(...)

Tepco workers standing before the stricken Fukushima Daiichi nuclear power plant on February 28th, 2012. Photograph: Yoshikazu Tsuno/AFP/Getty Images

David McNeill in Tokyo The Japanese government says it has agreed to compensate a man who contracted leukemia while working at the Fukushima Daiichi n(...)

US president Barack Obama. “I hereby direct you to take all necessary steps to give effect to the US commitments with respect to sanctions” on Iran. Photograph: Zach Gibson/The New York Times

The United States approved conditional sanctions waivers for Iran on Sunday, though it cautioned that they would not take effect until Tehran has curb(...)