VIENNA: A senior EU official is reporting no progress in the newest international push to persuade Iran to curb activities that could be used to make nuclear weapons, leaving the resumption of high-stakes negotiations with Tehran in doubt, diplomats said Friday.

A meeting Tuesday between senior EU envoy Helga Schmid and Ali Bagheri, Iran's deputy nuclear negotiator, was an attempt to restart top-level nuclear talks between Tehran and six world powers after the last round in Moscow fizzled on June 19.

Neither side wants to give up the talks. Iran seeks relief from sanctions, including recently enacted international embargoes on its oil, its main source of revenue. The U.S and other countries at the table with Tehran fear that the failure of negotiations could prompt Israel to make good on its threat to attack Tehran's nuclear installations - a move that could draw Washington into the conflict.

The six want the Islamic Republic to end enriching uranium to a level that can be turned quickly into fissile warhead material. Tehran refuses, says it is enriching only to make nuclear fuel and medical isotopes and insists it has a right to enrich under international law.

With no progress back in June, the two sides agreed to kick the talks down to low-level experts in an attempt to better understand each-others' positions.

That expert meeting in June was followed by the Schmid-Bagheri talks, which looked for signs of possible nearing of positions. But one of two diplomats told The Associated Press that Schmid has reported "no progress" to EU foreign policy chief Catherine Ashton, who in turn is informing the six powers - the U.S., Russia, China, Britain, France and Germany - of the results of the meeting.

EU officials said Thursday that Ashton will be talking to top Iranian nuclear negotiator Saeed Jalili soon on the next steps. That potentially could result in agreement on a new six-power Iran round.

But the second diplomat said the lack of progress at the talks Tuesday could more likely mean that Jalili and Ashton agree only to have another Schmid and Bagheri meeting - or an even lower-level encounter, again at the experts' level.

The two diplomats are familiar with the results of the Schmid-Bagheri talks. They demanded anonymity because they are not authorized to discuss the substance of that confidential meeting.

Both said that with armed conflict as a possible alternative the talks would continue on some level, a view that was also voiced Friday by Iran.

"The talks will be continued until they reach positive and constructive conclusions," said Ali Akbar Velayati, an adviser to the country's Supreme Leader Ayatollah Ali Khamenei, in comments cited by the semi-official ISNA news agency.

The six are offering to ease restrictions on airplane parts for Iran's outmoded, mostly U.S.-produced civilian fleet as well as technical help with aspects of Iran's nuclear program that cannot be used for military purposes.

Beyond wanting Tehran to stop enriching to a level just steps away from the purity needed to arm a nuclear missile they also demand that it shut down an underground plant where such work is taking place.

Iran in turn says that its right to enrich is enshrined in the nuclear nonproliferation treaty - and therefore sees demands to curtail higher enrichment as contravening international law.

It also refuses to shutter the underground facility, which it has fortified in anticipation of possible attack. Israel has warned of possible air strikes on Iranian nuclear facilities and the United States has said all options are on the table should negotiations fail to bring Tehran to compromise.

Iran is under four sets of U.N. sanctions and other embargos. An EU ban on Iranian oil came into full effect July 1, adding to U.S.-led sanctions on Iranian crude and further cutting into exports of OPEC's second-largest producer.