Nuclear talks between world powers and Iran start in İstanbul

"Delegates have gone in... plenary is just getting started," a diplomat close to the negotiations said.     

Diplomats say the round, the first in 15 months, is unlikely to result in a major breakthrough but offers a chance to resume dialogue and dampen speculation that Israel might launch military strikes to prevent its arch enemy from acquiring nuclear arms.     

Global fuel prices have risen this year amid deepening tensions over the nuclear programme, which Iran says is for peaceful purposes.