[caption id="attachment_155509" align="alignright" width="238"] US Secretary of State John Kerry speaks at a news conference in Sharm el-Sheikh on March 14, 2015. (AFP photo)[/caption]

The US Secretary of State has blasted an open letter to Iran by Republican senators as “incorrect”, saying Congress cannot revoke a possible nuclear deal with Iran.

John Kerry, speaking Saturday in Egypt, stressed that US President Barack Obama has the power to implement any agreement reached with Iran, despite intense opposition from Republican lawmakers in Congress.

"As far as we're concerned, Congress has no ability to change an executive agreement," Kerry told a news conference in Sharm el-Sheikh, where he was attending an economic conference.

“From our point of view, this letter is incorrect in its statements,” the top US diplomat said, adding that the American lawmakers were “wrong.”

An open letter signed last week by 47 Republican senators warned Iran that any nuclear deal may last only as long as President Obama remained in office. The move was a highly unusual intervention in US foreign policy.

Iran and the P5+1 countries – the US, Britain, France, China, Russia, and Germany – are holding negotiations to work out a final deal aimed at ending the longstanding standoff over the Islamic Republic’s nuclear program.

Kerry also said that Iran and the P5+1 have made some progress during the nuclear negotiations, but that "important gaps" remain ahead of the July 1 deadline.

At the same time, the senior US diplomat welcomed a formal religious ruling or “fatwa” by Iran’s Leader that bans nuclear proliferation.

The Leader of the Islamic Revolution, Ayatollah Seyyed Ali Khamenei, noted on Thursday that the GOP letter to Iranian officials revealed the collapse of political ethics in the US system.

President Obama has said he is "embarrassed" for the senators who signed the controversial.

"I am embarrassed for them," Obama said in an interview with VICE News, which is scheduled to be released Monday.

The letter followed a speech to Congress earlier this month by Israeli Prime Minister Benjamin Netanyahu, who warned US lawmakers that the White House was negotiating “a very bad deal” with Tehran.

By Press TV