As they opened arms-reduction talks, the United States and Russia were urged Tuesday to set aside their recent antagonism and unite to thwart Iran's pursuit of nuclear weapons.


That was the underlying message of two separate reports, released Tuesday, that address Tehran's growing nuclear ambitions as well as the falling out that has occurred between Washington and the Kremlin in recent years.


Russia's war last summer with neighbour Georgia, as well as former U.S. president George W. Bush's plan to base a missile defence shield in Eastern Europe to protect the greater continent against Iranian and North Korean missile launches, have strained relations between Moscow and Washington.


A coalition of leading American and Russian scientists concluded Tuesday that the Pentagon's proposed missile shield for Europe — a plan Russia views as a hostile — would do nothing to protect against an Iranian missile attack.


"If Iran were to attack Europe with more than one or two missiles, the European missile defence system as proposed could not defend Europe," says the report by the New York-based independent think-tank, the EastWest Institute.


The report urges U.S. President Barack Obama's new administration to "conduct a serious technical review of the capabilities" of the shield proposal, which would base sensors and interceptor rockets in Poland and the Czech Republic.


The Russian and American scientists urged the Kremlin and Washington to set aside their enmity over the missile shield and other irritants and join forces to find ways of containing Iran's nuclear program.


The scientists presented their report to Russian Foreign Minister Sergey Lavrov and U.S. National Security Adviser James Jones three months ago, and despite a deterioration in relations "not seen in decades," it received a positive reception providing "the basis for hope that both countries will be able to develop constructive policies of co-operation in addressing existing nuclear and missile threats."


Their report said the April 1, 2009, meeting between Obama and Russian President Dmitry Medvedev raised hope for a new beginning when the two leaders pledged to work together to reduce their nuclear weapons stockpiles.


A separate report prepared for the U.S. Air Force by the RAND Corporation, also released Tuesday, called on the United States to lower the tone of its hostile rhetoric towards Iran and consider embracing Russia.


"Over the years, the United States has attempted a variety of approaches to address the Iranian challenge. To date, none has succeeded," said the RAND report.


"We suggest leveraging international pressure while unilaterally de-escalating U.S. rhetoric and policy toward Iran (essentially, reversing the traditional good cop/bad cop roles)."


Support from Russia and China "is critical because it helps deprive the Iranian leadership of the ability to deflect domestic critique by focusing discontent solely on the United States and the United Kingdom or other European Union powers."


But the RAND report was less optimistic about the prospects of engaging with Russia or China, saying the likelihood of their continued support of the U.S. "remains questionable."


The Iranian nuclear question was front and centre when Israeli Prime Minister Benjamin Netanyahu visited the White House on Monday.


Obama has reached out to Tehran's ruling clerics, but Netanyahu wanted to push the U.S. president to give Iran only a few months to respond to his overtures on the nuclear issue.


Bristling at the suggestion of one Israeli reporter that reaching out to Iran suggested a sign of weakness, Obama said he would not accept an "artificial deadline" in his dealings with Iran, but that the U.S. remained steadfastly opposed to the country getting a nuclear weapon.


On Tuesday, U.S. and Russian officials began negotiations aimed at replacing the 1991 Strategic Arms Reduction Treaty, which expires in December.


But Lavrov warned that the new arms talks would not be easily separated from Russian concerns over the proposed U.S. missile shield.


"We believe that the START treaty cannot be discussed in a vacuum."