Iran nuclear deal: Obama says US partisanship gone too far
US President Barack Obama has said that partisanship over the Iran nuclear deal has gone too far.
He rebuked the stance of some Republicans in the US Congress.
But one of those criticised by the president - Senator John McCain - said that there were discrepancies between US and Iranian versions of the deal.
An outline agreement on the future shape of Iran's nuclear programme was reached after marathon talks with six major powers earlier in April.
Some Republicans have argued against the deal, saying that Iran has received too many concessions.
Mr McCain suggested last week that Secretary of State John Kerry's explanations of the framework agreement were "somehow less trustworthy" than those of Iran's supreme leader.
And he argued on Saturday that discrepancies between US and Iranian versions of the deal extended to inspections, sanctions relief and other key issues.
"It is undeniable that the version of the nuclear agreement outlined by the Obama administration is far different from the one described by Iran's supreme leader,'' Mr McCain said in a statement.
"I strongly agree with two of America's most eminent statesmen, former Secretaries of State Henry Kissinger and George Shultz, who last week laid out the serious consequences of this deal for our nation's security."
The deal aims to prevent Tehran making a nuclear weapon in exchange for phased sanction relief.
A deadline has been set for 30 June to reach a comprehensive pact. Tough negotiations still lie ahead.
President Obama, speaking after a regional conference in Panama, said he remained "absolutely positive'' that the deal was the surest way to prevent Iran obtaining nuclear arms,
Earlier, Iran's Supreme Leader Ayatollah Ali Khamenei said that a final agreement must result in an immediate end to all sanctions.
President Obama said on Saturday that Mr Khamenei was simply addressing his own country's internal politics.
"Even a guy with the title 'Supreme Leader' has to be concerned about his own constituencies," he said.
Mr Obama went on to criticise the attitudes of some Republican senators who have been highly sceptical about the emerging agreement with Iran.
Right to review
Mr Obama said that entrenched partisanship was no way to run foreign policy.
The framework agreement was announced by the European Union and Iran after eight days of negotiations in Switzerland.
The talks at Lausanne's Beau-Rivage Palace hotel between Iran and the so-called P5+1 - the US, UK, France, China and Russia plus Germany - continued beyond the original, self-imposed deadline of 31 March.
The outline agreement has also been criticised by members of Congress who want US lawmakers to have the right to review any final deal.