A senior Iranian official warned Tuesday that “dark forces” sought to sabotage a final nuclear deal between world powers and Tehran, perhaps in a veiled reference to Israel’s opposition to an agreement which would permit Iran to keep its uranium enrichment capabilities.

“There are spoilers everywhere who don’t want an agreement, there are dark forces who don’t like this process,” Deputy Foreign Minister Abbas Araqchi told The Guradian. “I don’t want to use the word ‘warmongers,’ but these people want continuing tension, a continuing crisis in our region.”

The third round of talks between Iran and world powers is scheduled to begin on May 13.

Israel has been opposed to the negotiations which it views as Iran’s means of stalling for time while producing enough fissile material for a nuclear weapon. Israel’s ambassador in Washington Ron Dermer said last month that a state interested in pursuing a program for peaceful purposes alone had no need to enrich its own uranium or to build underground facilities and heavy water plants, all things that Iran has done and seeks to retain as part of a final agreement with the P5+1 world powers.

Araqchi’s comments may also have referred to the US Congress, whose Republican representatives opposed the interim deal reached between Iran and world powers in November.

Though Araqchi said Iran’s negotiation efforts were supported by the majority of his country, he noted that they were also under pressure from hardliners who were “very critical” of any Iranian concessions

“We are hopeful. For our part, we are very serious and we have goodwill,” he told the Guardian. “If the other side reciprocates, hopefully we will come to an end. But anything can happen.”

He noted that Iran “could get 95 percent agreement and the last 5% percent could ruin everything.”

Araqchi, the deputy foreign minister for legal and international affairs, is one of the three Iranian officials leading the negotiations.

Iranian Foreign Minister Mohammad Javad Zarif said Tuesday that the Islamic Republic’s conciliatory approach on the nuclear issue has led to the international isolation of Israel.

“The government’s foreign policy has taken away peace and comfort from Netanyahu and has isolated him internationally and this is a great victory that all the resistance forces of the region have each appreciated us for,” he said, according to a translation by the semi-official Iranian Fars news outlet.

Supreme leader Ayatollah Ali Khamenei, who has the final say on key state affairs including nuclear policy, has lent qualified support to self-declared moderate President Hassan Rouhani to push for a permanent deal that would ultimately lift sanctions on Iran in exchange for curbs on its atomic drive.

AFP and AP contributed to this report.