Iran urged Western powers Tuesday to resist any pressure from third parties not directly involved in negotiations over its nuclear activities, in a clear reference to Israeli-led influence.

Foreign Minister Mohammad Javad Zarif, quoted by the official IRNA news agency after meetings with EU foreign policy chief Catherine Ashton, also called for “seriousness and realism,” in the next round of nuclear talks in Vienna next month.

After a second day of discussions with Ashton in Istanbul, Zarif said the P5 + 1 powers (Britain, China, France, Russia, the United States and Germany) should avoid “illusions which might be exerted on them by some pressure groups and people outside the negotiations.”

Iran has consistently denied it is seeking nuclear weapons but wants an independent atomic energy program. Israel and lawmakers in the US Congress have repeatedly warned against lowering the pressure on Iran.

Zarif also said reaching an agreement was “completely possible” and that the Islamic republic would participate in the talks with “seriousness, accuracy and without any rush.”

He condemned as “brutal obstacles” the sanctions imposed on Iran over its nuclear activities, pledging that their eventual removal was “the basis of our work” in seeking a comprehensive deal that would “preserve the rights and dignity of the nation.”

The next round of talks on resolving Western concerns will take place in Vienna on June 16-20, the European Union announced earlier Tuesday.

Talks earlier this month made no “tangible progress,” with a July 20 deadline for a conclusive agreement looming on the horizon and major issues still outstanding.

These reportedly include the scope of Iran’s enrichment of uranium, which if further purified could be used to trigger a nuclear explosion, and its unfinished Arak research reactor, whose by-product waste could provide an alternative route to an atomic bomb.

The differences during the last round in Vienna prevented a start being made on an early draft agreement.

Negotiators aim to nail down an exceedingly complex and lasting deal limiting Iran’s nuclear activities in exchange for a lifting of sanctions.

Failure could have calamitous consequences, potentially sparking conflict — neither Israel nor the United States rules out military action — and creating a nuclear arms race in the Middle East.

Negotiators could theoretically extend the July 20 deadline to win more time, but presidents Barack Obama and Hassan Rouhani could struggle to keep skeptical and impatient US and Iranian hardliners at bay.