Still, we'll continue to pursue patty-cake with this bunch

The latest statement from the Ayatollah Khameini isn't exactly a ringing endorsement of the nuke negotiations' prospects.

"Some of the officials of the previous government as well as the officials of this government think the problem will be resolved if they negotiate the nuclear issue,” Khamenei said in remarks published on his website Khamenei.ir.

"I repeat it again that I am not optimistic about the negotiations and they will lead nowhere, but I am not against them," he added.

Iran is due to resume talks on Tuesday in Vienna with the P5+1 powers -- Britain, France, the United States, Russia and China plus Germany -- aimed at reaching a comprehensive accord on its controversial nuclear programme.

Under a landmark interim deal clinched in November, Iran agreed to freeze some nuclear activities for six months in exchange for modest sanctions relief and a promise by Western powers not to impose new restrictions on its hard-hit economy.

Western powers and Israel have long suspected Iran is pursuing a nuclear weapons capability alongside its civilian programme, charges denied by Tehran.

Khamenei said Iran would abide by its pledge to pursue the negotiations, adding that Iranian officials should "continue their efforts".

"The work that has been started by the foreign ministry will continue and Iran will not violate its commitment, but I repeat it again, it will lead to nowhere," Khamenei said.

"The Iranian nation emphasised that it will never succumb to the bullying and blackmailing of America," said Khamenei, referring to anti-US slogans chanted by huge crowds during nationwide celebrations last week of the 35th anniversary of country's Islamic revolution.

Add in the recent failed talks over the Syrian civil war, and the picture is not one of a West able to shape dynamics on the world stage.