Reuters quoted Iran's chief nuclear negotiator, Ali Bagheri, as saying that the European countries failed to present any constructive proposal or initiative amid efforts to revive the 2015 agreement signed with Iran, while the G7 countries reiterated the need for Iran to stop what it described as its nuclear escalation.

Bagheri said - in statements to PressTV - that the European parties - in reference to Britain, France and Germany, which are among the major powers trying to save the agreement - failed to come up with any initiative to resolve differences regarding lifting sanctions on Iran.

A source in the Iranian negotiating delegation in Vienna told Al Jazeera that negotiations are continuing in earnest, and are dealing with Iranian proposals.

The Iranian source stated that the European trio presents exaggerated points that slow down the progress of the negotiations, as he put it. The source stressed that Tehran strongly rejects European pressure to include demands from outside the nuclear agreement.

As for the major international powers, the foreign ministers of the seven countries reiterated the need for Iran to stop its nuclear escalation.

British Foreign Secretary Liz Truss said that the Vienna talks represented the last chance for Tehran to return to the nuclear deal negotiating table.

She added - on the sidelines of the Group of Seven foreign ministers summit in Liverpool - that these countries will not allow Iran to possess a nuclear weapon.

The British minister also urged Tehran to make what she described as a serious offer at the negotiating table, and said that it still had time to do so.

It is noteworthy that the indirect negotiations between Iran and the United States resumed - mediated by the Europeans in particular - at the end of last November in Vienna in an attempt to save the nuclear agreement concluded in 2015 aimed at preventing the Islamic Republic from acquiring nuclear weapons.

The 2015 agreement allowed for the lifting of many sanctions imposed on Tehran, in exchange for restricting its nuclear activities and ensuring the peacefulness of its programme.

However, the effects of the agreement have become null and void since the United States decided to unilaterally withdraw from it in 2018, during the era of former President Donald Trump, who re-imposed severe sanctions on Tehran.

For its part, the latter, about a year after the US withdrawal, has gradually retreated from implementing most of its basic obligations under it.

Israeli preparedness

While Israel is closely following the development of the talks in Vienna, Israeli newspapers indicate that it has entered the stage of military readiness.

The newspaper "Yediot Aharonot" quoted a senior official that there is no American opposition to an Israeli attack on Iran.

As for Haaretz newspaper, it reported that on Saturday, Israeli Defense Minister Benny Gantz ordered the army to prepare for the possibility of a military strike on Iran.

While the Jerusalem Post reported that Gantz put the Americans - during his meeting with them last Thursday - in the picture of the timetable that his army needs to attack Iran.

The Jerusalem Post quoted a senior diplomatic source as saying that the Americans did not express their opposition to the Israeli preparations when Gantz offered them the deadline.

Iranian warning

On the other hand, Iranian official media reported that a senior Iranian military official vowed on Saturday to the "aggressors" to pay a "heavy price", after publishing a report on US-Israeli plans to conduct possible military exercises in preparation for strikes on Iranian nuclear sites if diplomacy fails.

And Noor News Agency, which is affiliated with Iran's highest security apparatus, stated - in a tweet on Twitter - quoting an unnamed military official that "allowing the military leaders to test Iranian missiles on real targets will cost the aggressors a heavy price."

Earlier, two prominent Iranian officials warned that any Tel Aviv attack on Iranian facilities would mean the end of Israel, and stressed that Tehran was "fully prepared" to destroy Israel.