Washington, March 11  Louisiana’s Indian-American governor Bobby Jindal has jumped into a war of words between the White House and Senate Republicans over a letter to the government of Iran on a potential deal over its nuclear programme.

Jindal, who is testing the waters for a 2016 presidential run, issued a call on Tuesday for “all potential presidential candidates” to sign on the letter signed by 47 Republican senators.

These include four who are considered potential candidates in the 2016 presidential race: Ted Cruz (Texas), Lindsey O. Graham (South Carolina), Rand Paul (Kentucky) and Marco Rubio (Florida).

The letter, organized by Senator Tom Cotton, warned Iran that if Congress did not formally approve a nuclear agreement, it could then be disregarded or modified under a future president.

Jindal, in a statement released on Tuesday, said that others who might get into the race should sign on, too, according to the Washington Post.

“Every single person thinking about running for president, on both sides, should sign on to this letter to make clear to Iran that they are negotiating with a lame duck president,” Jindal said in a statement issued through an outside group he leads, America Next.

“Make no mistake – any Iran deal that President Obama makes is not binding on a future president,” he was quoted as saying.

The Post cited a spokesperson for Jindal as saying he had “signed on” to the letter on Tuesday morning by sending an e-mail to Cotton’s office, and Cotton’s office released a statement later in the day saying that Jindal is now considered a signatory to the letter.

Former Republican Texas governor Rick Perry echoed Jindal’s sentiments, the Post said, tweeting on Tuesday that he “would be proud and honoured to sign the letter @SenTomCotton has put forward on Iran”.

In his statement on Tuesday, Jindal also renewed his criticisms that Obama was not willing to confront – or even admit – the true scope of the threat from Islamist groups and Iran.

Jindal also said that Vice President Biden – who had criticised the letter as “beneath the dignity” of the Senate – should apologise to Cotton, who served in the army before running for office.

“Vice President Biden owes Senator Cotton an apology. He wore the boots in Iraq. He’s earned our attention, not your insults. I’m glad some senators are showing leadership in the absence of leadership from the White House,” Jindal was quoted as saying.

A White House spokesman derided the letter as “reckless” and “irresponsible”. Obama said that it appeared as though the Republicans were trying to make common cause with Iran’s hard-line mullahs to quash any potential agreement.

Former secretary of state Hillary Rodham Clinton also attacked Republicans who had signed the letter to Iran.

But Republicans faulted the White House for its repeated failures to consult with Congress as the negotiations progressed.

At the State Department a reporter pointed out that two years ago, around 20 US senators and over 120 members of the House of Representatives had written directly to Indian prime minister on economic reforms.

“It’s an entirely different thing,” State Department spokesperson Jen Psaki responded. “We’re talking about inserting yourself into international negotiations that are ongoing — that involve the executive branch.”