US Secretary of State John Kerry has arrived in Vienna for talks with foreign ministers about Tehran's nuclear program.
Iran and the six powers- Britain, the US, France, Germany, Russia and China- aim to reach a long-term deal to end the decade-old nuclear standoff by July 20.
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At least three children and 18 others - including members of the local police force - were among those who died.
The Foreign Secretary was unable to rule out the possibility of continuing to pay money into the EU when he spoke to Peston On Sunday.
He told Peston on Sunday: "The country is crying out for leadership from the Prime Minister. We want to know her vision."