VIENNA - US Secretary of State John Kerry said on Sunday major differences persist between Iran and six world powers negotiating on Tehran's nuclear program, remarks echoed by Tehran, with a July 20 deadline for a deal approaching.

The United States, Britain, France, Germany, Russia and China want Iran to reduce its nuclear fuel-making capacity to deny it any means of quickly producing atom bombs. In exchange, international sanctions that have crippled the large OPEC member's oil-dependent economy would gradually be lifted.

Iran says it is enriching uranium for peaceful energy purposes only and wants the sanctions removed swiftly. But a history of hiding sensitive nuclear work from UN inspectors raised international suspicions and the risk of a new Middle East war if diplomacy fails to yield a long-term settlement.

"Obviously we have some very significant gaps still, so we need to see if we can make some progress," Kerry said ahead of meetings with European Union foreign policy chief Catherine Ashton and other EU foreign ministers who flew into the Austrian capital at the weekend to kick-start the faltering talks.

Please LIKE our Facebook page - it makes us stronger