Iran’s main focus in nuclear talks that resume in Austria on Dec. 27 will be the lifting of all U.S. sanctions in a verifiable process that guarantees Tehran’s unhindered ability to export its oil, Iran's foreign minister said.

Negotiations with world powers to salvage Iran's 2015 nuclear accord, the Joint Comprehensive Plan of Action (JCPOA), are to resume in Vienna, state media reported.

"The most important issue for us is to reach a point where, firstly, Iranian oil can be sold easily and without hindrance,” Iranian media quoted Foreign Minister Hossein Amirabdollahian as saying.

"The money from the oil (sales) is to be deposited as foreign currency in Iranian banks - so we can enjoy all the economic benefits stipulated in Joint Comprehensive Plan of Action."

In 2018, then U.S. President Donald Trump withdrew from the JCPOA and reimposed stringent economic sanctions against Tehran, which responded a year later by resuming and then accelerating its enrichment of uranium, a potential pathway to nuclear weapons.

Oil exports, Iran’s main revenue source, have plunged under the U.S. sanctions. Tehran does not disclose data, but assessments based on shipping and other sources suggest a fall from about 2.8 million barrels per day (bpd) in 2018 to as low as 200,000 bpd. One survey put exports at 600,000 bpd in June.

The nuclear talks have made scant progress since they resumed last month after a five-month hiatus following the election of hardline Iranian President Ebrahim Raisi.

“Today, there is an acceptable joint document on the negotiating table that we call the December 1 and December 15 documents,” Amirabdollahian said. Both documents, he said, related to the nuclear issue as well as U.S. sanctions.

“From today, our negotiations will start on the basis of this joint document. Guarantees and verification are among the issues on the agenda,” Amirabdollahian said.

An Iranian official close to the negotiating team told Reuters that "Iran will not accept any interim deal", as had been suggested by some parties.

Iran's two draft texts, submitted in previous talks, were incorporated in a draft drawn up in June after six rounds of talks between the former Iranian team and major powers.

Under the 2015 deal, Iran limited its uranium enrichment program in return for relief from U.S., EU and U.N. economic sanctions. Iran says its nuclear program is for solely peaceful purposes.

At the last round of talks, senior British, French and German diplomats offered a pessimistic assessment of efforts to revive the deal. U.S. National Security Adviser Jake Sullivan last week said that the United States and its partners were discussing timeframes for nuclear diplomacy with Iran, adding that the current talks could be exhausted within weeks.

Iranian Foreign Ministry spokesman Saeed Khatibzadeh on Dec. 27 said that the Iran side would not accept any deadlines. A source close to Iran’s team told Reuters that the delegation would stay in Vienna for as long as is needed.

Iran's arch foe, Israel, which is not involved in the talks, said the main challenge was "preventing a nuclear Iran".

"Israel is not opposed to any deal," Israeli Foreign Minister Yair Lapid told parliament's Foreign Affairs and Defense Committee in Jerusalem on Monday.

"A good deal would be good. We oppose a deal that does not enable true oversight over the Iranian nuclear program, nor over the Iranian money, nor over the Iranian terror network."