LAUSANNE, Switzerland—Efforts by the Obama administration to stem criticism of its diplomacy with Iran have included threats to nations involved in the talks, including U.S. allies, according to Western sources familiar with White House efforts to quell fears it will permit Iran to retain aspects of its nuclear weapons program.

A series of conversations between top American and French officials, including between President Obama and French President Francois Hollande, have seen Americans engage in behavior described as bullying by sources who spoke to the Washington Free Beacon.

The disagreement over France’s cautious position in regard to Iran threatens to erode U.S. relations with Paris, sources said.

Tension between Washington and Paris comes amid frustration by other U.S. allies, such as Saudi Arabia and Israel. The White House responded to this criticism by engaging in public campaigns analysts worry will endanger American interests.

Western policy analysts who spoke to the Free Beacon, including some with close ties to the French political establishment, were dismayed over what they saw as the White House’s willingness to sacrifice its relationship with Paris as talks with Iran reach their final stages.

A recent phone call between Obama and Hollande was reported as tense as the leaders disagreed over the White House’s accommodation of Iranian red lines.

Amid these tensions, U.S. Ambassador to France Jane Hartley met with her French counterpart, Gerard Araud, Monday to discuss a range of issues.

Benjamin Haddad, who has advised senior French political figures on foreign policy issues, said leaders in Paris have not been shy about highlighting disagreements they have with the White House.

"Fance, like other European countries, has negotiated for more than 10 years and endured most of the sanctions’ burden," said Haddad, a research fellow at the Hudson Institute.

"The French want a deal, but they see no rush and repeat that Iranians need a deal more than we do, and that we shouldn't fix artificial deadlines that put more pressure on us than Iran."

One source in Europe close to the ongoing diplomacy said the United States has begun to adopt a "harsh" stance toward its allies in Paris.

"There have been very harsh expressions of displeasure by the Americans toward French officials for raising substantive concerns about key elements of what the White House and State Department negotiators are willing to concede to Iran," said the source, who spoke on condition of anonymity. "That is because the clarifications expose just how weak the Americans’ deal is shaping up to be."

"The meeting between the French ambassador in Washington and the president's envoy to Paris—not a diplomat but a big fundraiser for his campaigns—comes amid these very harsh words that were spoken privately about the ambassador's recent comments on the seeming American desperation for a deal, and the tough words that President Obama had for President Hollande in their phone call."

Strategic differences remain between the United States and its allies over how a final deal should look, the source said. The French remain opposed to a recent range of concessions made by the Obama administration.

"We may agree that denying Iran a nuclear weapon ability is the goal, but apparently the view of what one can leave Iran and assure that is very different," the source said.

"Clearly these are the differences that must be discussed. I don't see France suddenly deciding that America is right and French objections to weakness are wrong, nor that silence is preferable to transparency."

Haddad said the French are hesitant to rush into an agreement.

"The French want a robust deal with clear guarantees on issues like [research and development] and inspections to ensure that Iranians won't be able to reduce breakout time during the duration of the agreement (also an issue of discussion), or just after thanks to research conducted during the period," he said. "That is also why they disagreed on lifting sanctions."

He also said the French "don't trust Iran and believe an ambiguous deal would lead to regional proliferation."

Another Western source familiar with the talks said the White House is sacrificing longstanding alliances to cement a contentious deal with Iran before Obama’s term in office ends.

"The President could be hammering out the best deal in the history of diplomacy, and it still wouldn't be worth sacrificing our alliances with France, Israel, and Saudi Arabia—key partners in Europe, the eastern Mediterranean, and the Gulf," the source said. "But he's blowing up our alliances to secure a deal that paves Iran's way to a bomb."

A State Department spokesperson declined to comment on the issue.

Meanwhile, talks between the United States and Iran reached a critical juncture Thursday, as Secretary of State John Kerry met with his Iranian counterpoint to hash out differences over key points concerning Iran’s nuclear program.

The sides are hoping to reach a framework agreement by March 31 amid reports that Iran is demanding Saudi Arabia immediately halt airstrikes in Yemen, where Iran-aligned forces are working to bring down the Western-backed government.

The issue could complicate the talks as the United States attempts to balance its regional alliance with Iran in Iraq against competing interests with traditional allies in Saudi Arabia.

U.S. negotiators have reportedly softened their stance in recent days on a range of issues relating to Iran’s continued production of nuclear materials. One of Iran’s nuclear sites in Fordow could continue to operate, according to the Associated Press.