Iran's President-elect Hassan Rohani. Photo: Wikipedia.

A group of liberal Democrat politicians in the US are speaking out against a tough new Iran sanctions bill set to be put to a vote in Congress on Wednesday, Foreign Policy’s Cable Blog reported on Monday.

Reps. Jim McDermott, John Conyers, Keith Ellison and Jim McGovern wrote a letter urging House leadership to delay the vote on the bill which they fear could jeopardize efforts by the Obama Administration to engage Iran’s newly-elected President Hassan Rouhani on the country’s nuclear program.

“We believe that it would be counterproductive and irresponsible to vote on this measure before Iran’s new president is inaugurated on August 4, 2013,” reads the letter. “A diplomatic solution remains the best possible means for ensuring that Iran does not acquire a nuclear weapon, and the House of Representatives should not preempt a potential opportunity to secure such an outcome with another sanctions bill.”

According to Foreign Policy, an aide for Ellison is currently collecting signatures for the letter with a deadline of Tuesday at noon. “Regardless of whether your boss supports [the bill], it could not come at a worse time,” reads a note by Senior Legislative Assistant Stephen Lassiter. “Iran’s new president, Hassan Rouhani, who campaigned on improving relations with the West, takes office in two weeks.”

While the vote is expected to pass Wednesday, Foreign Policy writes that it may be a more narrow vote than those previously involving Iran’s nuclear program. “That uncertainty stems from a surprisingly successful bipartisan letter signed by nearly a third of the House in June calling for a diplomatic solution to the conflict over Iran’s nuclear program,” writes Foreign Policy.

The dispute highlights the increasingly dissonant approaches to the issue by the White House and the Republican-controlled Congress. President Barack Obama last week eased sanctions on Iran and is planning to engage with Rouhani, who has been hailed by many as a relative moderate, on the nuclear issue in September, while the House wants to continue to hit at Iran’s oil exports and, possibly, its banking sector.

Earlier this month Israeli Prime Minister Netanyahu described Rouhani as “a wolf in sheep’s clothing.”