U.S. Secretary of State John Kerry said on Sunday world powers would pursue further talks with Iran to resolve a decade-old dispute over its nuclear programme, but stressed the process could not go on forever.

World powers and Iran failed again to bridge the gap at weekend talks in Kazakhstan, prolonging a stand-off that could yet spiral into a new Middle East war. No new talks were scheduled between Iran and the six powers.

“This is not an interminable process,” said Kerry after arriving in Istanbul on Sunday on the first leg of a 10-day trip to the Middle East, Europe and Asia.

He said U.S. President Barack Obama was committed to continuing the diplomatic process despite what he called the complicating factor of an Iranian presidential election in June.

“Diplomacy is a painful task … and a task for the patient,” Kerry told a news conference.

Israeli Strategic Affairs Minister Yuval Steinitz urged the powers on Sunday to set a deadline of weeks for military action to persuade Iran to halt its nuclear enrichment activity.

Steinitz, who is close to Prime Minister Benjamin Netanyahu, told Army Radio action should be taken within “a few weeks, a month” if Iran did not stop its sensitive nuclear programme, which Israel sees as a potential threat to its existence.

Western powers suspect Iran is trying to develop the means to produce nuclear weapons behind the guise of a declared civilian atomic energy programme. Iran denies the accusation.

Tehran accuses Israel of threatening peace in the region and refuses to recognise the Jewish state, which is widely believed to harbour the Middle East’s only nuclear arsenal.

European Union foreign policy chief Catherine Ashton, who represents the United States, Russia, China, France, Britain and Germany in talks with Iran, said the two sides failed to resolve key differences during the two-day talks in Almaty.

“… It is important to continue to talk and to try to find common ground,” Kerry said. “So we hope that out of Almaty will come a narrowing of some of the differences. We remain open and hopeful that a diplomatic solution can be found.”

The six powers want the Islamic Republic to suspend its higher-grade uranium enrichment work in return for modest relief from international sanctions, an offer Iran did not accept.

Some diplomats and experts have said Iran’s June presidential election has raised uncertainty in the West over the Islamic Republic’s strategy for nuclear diplomacy.

“Obviously there is an election and that complicates the choices with respect to the politics of Iran, and we are aware of that,” Kerry said.

“But we will continue. The president (Obama) has determined to continue to pursue the diplomatic channel … We remain open and hopeful that a diplomatic solution can be found.”

(Reuters)