Iran and world powers plan to adjourn their high-profile negotiations on Monday after again missing a deadline to clinch a final deal.

The deadline for the talks will be extended to July 1, 2015 in an attempt to secure a comprehensive deal on Tehran's nuclear program, Iran's official IRNA news agency reported.

The US's careful approach, one that seeks to maintain a balance between traditional allies and Tehran against the backdrop of a rapidly evolving Middle Eastern political environment brought about by the rise of the Islamic State (IS), has taken its toll on the Iran nuclear talks, said analysts.

The talks are expected to reconvene next month, with Iranian President Hassan Rouhani scheduled to address the Iranian people later on Monday.

British Foreign Secretary Philip Hammond said that Iran and the powers "made some significant progress," and that there was a clear target to reach a "headline agreement" of substance within the next three months.

(Left to right) German Foreign Minister Frank-Walter Steinmeier, Chinese Foreign Minister Wang Yi, former EU foreign policy chief Catherine Ashton, French Foreign Minister Laurent Fabius, British Foreign Secretary Philip Hammond, US Secretary of State John Kerry and Russian Foreign Minister Sergey Lavrov pose for a photograph prior to a meeting of the closed-door nuclear talks with Iran, in Vienna, Austria, on Monday. Photo: AFP

 
The five permanent members of the UN Security Council, the US, Britain, France, Russia and China, plus Germany (the P5+1) have been locked in talks with Iran for months, seeking to turn an interim deal into a lasting accord.

Western diplomats said that Iran's uranium enrichment capacity and the number of centrifuges have kept the negotiation deadlocked while Iran claimed that the stumbling block is the removal of all the sanctions.

Iran's regional foes Israel and Saudi Arabia are watching the Vienna talks nervously. Both fear a weak deal may fail to curtail Tehran's nuclear ambitions. Israeli Prime Minister Benjamin Netanyahu told the BBC on Monday that he welcomed the likelihood that Iran and the six world powers would fail to meet a deadline.

"No deal is better than a bad deal. The deal that Iran was pushing for was terrible. A deal would have left Iran with the ability to enrich uranium for an atom bomb while removing the sanctions," Netanyahu said.

"An extension of negotiations is no surprise given the level of complexity of the Iran nuclear talks. For starters, years of hostility have left [Iran and the West] with little political trust. Plus, some regional countries, such as Israel and Saudi Arabia, the traditional US allies in the area, are not keen to see relations between the US and Iran warm up," said Li Weijian, a scholar with the Shanghai Institutes for International Studies.

"Various consultations with these countries have made some adjustments to the talks," Russia's TASS News Agency quoted a source in a Western delegation as saying on Sunday. "They are rather negative for the negotiating process but everything is relative."

"[Despite various factors], the bigger trend is that both sides are still working toward a deal … Judging from the relatively positive rhetoric and the extension of negotiations, the US has softened its longtime hard-line stance toward Iran and does not want to leave their ties strained … It is possible that a comprehensive deal may eventually be reached," Li said.

"The US focus in the Middle East has gradually shifted over the past years and its interests have grown more convoluted, especially after the rise of the IS … The coalition the US built to combat the IS has so far been ineffective. The US understands that its war against the jihadist group would be almost impossible to win without Iran's help," Dong Manyuan, a research fellow at the China Institute of International Studies, told the Global Times.

Meanwhile, an Iranian senior official said the country could turn to Beijing and Moscow if talks in Vienna fail to end Western sanctions, the Iranian Students' News Agency reported on Monday.

The official declined to reveal more details but said "if the nuclear talks fail, we will increase our cooperation with our friends and will provide them more opportunities in Iran's high-potential market."

Agencies contributed to this story