Israel has yet to say whether it would attend the proposed meeting and the senior Finnish official organizing it, Jaako Laajava, underlined at the weekend the importance of all Middle Eastern countries taking part.

“All the signs are that they are going to end up postponing it,” the envoy in Vienna said, referring to Laajava and the three powers which have tried to make the conference happen - the United States, Britain and Russia.

But diplomats stressed that efforts would continue to organize the conference at the earliest possible date. It is a case of “when rather than if,” another envoy said.

Even if the talks were to be organised eventually, Western diplomats and others expect little progress any time soon due to the deep-rooted animosities in the region.

Iran used a seminar in Brussels also attended by officials from Israel last week to announce it would go to the proposed meeting and “participate actively.”

The Islamic state is in a stand-off with world powers over suspicions it is seeking the means to produce nuclear weapons. Israel has not ruled out military action against Iranian nuclear sites.