TEHRAN, Iran 

US President Joe Biden said last week in Jerusalem on the first leg of his Middle East tour that Washington is "not going to wait forever" for Iran to revive a 2015 agreement on its nuclear program, hours after warning of using force against Tehran "as a last resort.”

During the four-day trip, which also took him to Saudi Arabia's port city of Jeddah for bilateral talks and a regional summit, Biden made it clear that the US will be acting tough against Iran despite ongoing negotiations in Doha to revive the nuclear accord, officially known as the Joint Comprehensive Plan of Action (JCPOA).

"The only thing worse than the Iran that exists now is an Iran with nuclear weapons," he said in an interview with Israel's Channel 12, sparking angry reactions from Tehran.

The first round of European Union-mediated Iran-US talks last month, as a follow-up to the Vienna talks, failed to produce the result "the EU team as coordinator had hoped for," the EU’s envoy, Enrique Mora, admitted on Twitter.

The next round, said many US and European officials, would be held after Biden's long-delayed trip and consultations with regional allies, most prominently Israel.

With the US president back from the regional trip, the question everyone seems to be asking is when will the Doha talks resume and whether there is a likelihood of two arch foes burying the hatchet and restoring the landmark deal that was effectively put on the backburner after the US withdrawal in 2018.

"The deal is hanging by a thread, especially after President Biden's Israel visit and the declaration issued jointly by Biden and the Israeli premier, which raised eyebrows in Tehran," Mohsen Salehi, a Tehran-based Middle East affairs analyst, told Anadolu Agency.

Mohsen believes the road to peace and rapprochement between Iran and the US, who have had no diplomatic relations since the 1979 Iranian revolution, has become "bumpier" after Biden's Middle East trip, especially his statements against Tehran.

- Iran-US talks in Doha

On July 14, Biden and Israeli Prime Minister Yair Lapid unveiled a joint declaration in Jerusalem boosting military cooperation between the two all-weather allies and reiterating calls to take military action against Iran's nuclear program.

The statement, officially known as the Jerusalem US-Israel Strategic Partnership Joint Declaration, asserted that the US will "never allow Iran to acquire a nuclear weapon" while adding that it is "prepared to use all elements of its national power to ensure that outcome."

It further said that the US reaffirms its commitment to "work together with other partners to confront Iran's aggression and destabilizing activities" in the region.

Hours later, Iran's President Ebrahim Raisi vowed a "harsh and regrettable response" to any "mistake" from the US or its allies.

A day later, on the second leg of his regional tour in Jeddah, Biden and Saudi Crown Prince Mohammed bin Salman addressed a regional summit, which was followed by a communique that again aimed at Iran's nuclear program and regional activities.

The statement "underscored the need to further deter Iran's interference in the internal affairs of other countries, its support for terrorism through its armed proxies, and its efforts to destabilize the security and stability of the region."

Already miffed by the Jerusalem Declaration, Iran's Foreign Ministry took strong exception to the Jeddah communique, accusing the US of fueling "tension and crisis" in the region by resorting to "Iranophobia."

Vahid Moradian, a senior journalist and political observer, said Biden's "overt anti-Iran posturing" during his Middle East visit and the "strong reactions" from Iranian officials don't augur well for the nuclear deal.

"From what we noticed in Doha last month, and in Vienna before that, there is a massive trust deficit between the two sides that is preventing an agreement," he told Anadolu Agency, adding Biden's visit to the Middle East has "only made it worse.”

Moradian, however, said the attempts to build a "regional front" against Iran during Biden's visit "didn't work out," as was evident from statements by both Saudi and Iranian officials after the Jeddah summit.

"The Saudi foreign minister again extended an olive branch to Iran, while the Iranian Supreme Leader's adviser welcomed it," he noted, adding the tension-easing talks between the two estranged neighbors in Baghdad are "unlikely to be affected" by Biden's trip.

- Saudi-Iran talks in Baghdad

The marathon talks between Saudi Arabia and Iran, brokered by the Iraqi government, have been underway since April last year, without any breakthrough so far.

Saudi Foreign Minister Prince Faisal bin Farhan Al Saud, speaking to reporters after the Jeddah summit, said talks with Tehran have been "positive," adding Riyadh is "keen on finding a path" to normalizing ties with Iran.

"The issue of forming a regional coalition consisting of Israel and Arab countries was in Biden's plan, but he failed to achieve that goal as countries in the region do not want to lead the region to tension and war," Seyyed Ali Nejat, a foreign policy analyst and writer, told Anadolu Agency.

He said a "soft position" was adopted against Iran at the Jeddah summit, but "it will not have a significant impact" on negotiations.

The two countries severed their diplomatic relations in 2016 following the execution of Saudi Shia cleric Sheikh Nimr al-Nimr, which saw unruly protesters storming Saudi diplomatic missions in Tehran and Mashhad.

At the weekly press briefing Wednesday, Iran's Foreign Ministry spokesman Nasser Kanaani said the talks are "moving forward," lauding the role played by Baghdad in bringing the two neighbors closer.

"What's clear is that the Iran-Saudi talks are most likely to move to the level of foreign ministers in the near future and even the opening of embassies, which can partly be attributed to strains in US-Saudi ties," said Salehi.

"But the same cannot be said about the Iran nuclear deal talks, as both sides have taken confrontational positions, which was on full display during Biden's Mideast visit."