"The negotiators should insist on the stances that have been announced and I hope they could meet the country's and the ruling systems system's interests," Ayatollah Khamenei said in a meeting with Iranian Parliament Speaker Ali Larijani and parliamentarians in Tehran on Wednesday.

Yet, the Supreme Leader underlined that the Iranian negotiators are engaged in hard work and efforts.

"There are many solutions to the nuclear issue all of which rely on the domestic capacities and reinforcing (domestic) production," Ayatollah Khamenei added.

The Supreme Leader underlined that the nuclear issue is only a pretext to pressure Iran and even if this problem is resolved, the western powers would seek other excuses such as "human rights".

Ayatollah Khamenei called on the Iranian officials to rely on the country's domestic capabilities, and said, "If we boost production and use domestic potentialities, this will not only solve internal problems, but also facilitate settlement of foreign issues such as the nuclear one," Ayatollah Khamenei added.

Earlier this month, Iran's Supreme Leader Khamenei dismissed the US war rhetoric against Iran as empty, boastful remarks, but meantime, warned that Tehran would not negotiate under threat.

"This is not acceptable that the opposite side continues making threats simultaneous with the talks," the Leader said, addressing a public meeting with teachers here in Tehran.

He further noted the remarks made by two US officials in recent days who had alleged that military threats against Iran are still alive, and said, "Negotiation under the ghost of a threat is meaningless and the Iranian nation does not tolerate negotiation under the shadow of threat."

"First of all, you can't do a damn thing," Ayatollah Khamenei said in response to the two US officials, and added, "Secondly, as I had already stated during the term of the former US president, the era of hit-and-run attacks is gone and the Iranian nation will not let go anyone intending to make an aggression" against it.

Meantime, he said the US needs the nuclear talks, at least, as much as Iran does, and pointed out that Iran is willing to put an end to the sanctions, while the US officials need to leave a legacy behind as "they are deeply in need to make this claim that they have made Iran sit to the negotiating table and imposed certain points on it".

The Supreme Leader underlined that now everyone in Iran knows pretty well that the country's economic problems are not resolved through the removal of the sanctions, "rather resolving economic problems requires our own planning, will and ability, no matter the sanctions are in place or not".

"Of course, if the sanctions are removed, the economic problems could be solved more easily, but their resolution will be possible if the sanctions continue," he added.

The Iranian leader further reminded the country's team of negotiators once again to pay good heed to the redlines, "but never allow the other side to impose its will, exercise force, humiliate or threaten you".

US Secretary of State John Kerry in a charm offensive to rebuild ties with Israel over the Iran policy said recently that military action is still among possible options for Washington.

On Tuesday, Iranian Foreign Minister Mohammad Javad Zarif complained about the difficulty of drafting a final deal between Tehran and the world powers, and called on the other side to adopt a realistic and pragmatic view to make a comprehensive agreement possible.

The process of drafting the Joint Plan of Action is difficult, Zarif said in a meeting with his Omani counterpart Yusuf bin Alawi in Muscat.
"The nuclear negotiations can end up in results if the other side shows pragmatism," he added.

After nine days of hard work in Lausanne, Switzerland, Iran and the Group 5+1 reached an understanding on April 2 which laid the ground for them to start drafting the final nuclear deal over Tehran's nuclear energy program ahead of a July 1 deadline.

Reading out a joint statement at a press conference with EU foreign policy chief Federica Mogherini in Lausanne on April 2, Zarif said according to the agreement, all the US, EU and UN Security Council sanctions against Iran would be lifted under the final deal.

The seven nations are now drafting the final deal.

But earlier this month, Head of the Atomic Energy Organization of Iran (AEOI) Ali Akbar Salehi complained that the world powers welsh on what they agree to undertake in the nuclear talks with Iran.

"We welcome interaction as Iran's logic is based interaction with the world. We are not after confrontation," Salehi said in Tehran, addressing a ceremony to commemorate the Iranian nuclear scientists assassinated by the foreign spy agencies.

He said the nuclear negotiations with the G5+1 are progressing well, but "they are lowballing with regard to certain issues that we had agreed on."

Salehi underscored that Tehran is after a nuclear agreement with the world powers "but not at any price".

His remarks came after the US Senate advanced a legislation that would allow the Congress to review a nuclear deal between world powers and Iran. The bill turned into a law by President Obama's endorsement.