The U.S. House of Representatives has passed a bill that would impose new sanctions on Iran.
Just days before Iran’s new president is sworn into office, the House voted 400 to 20 on July 31 to approve the bill.
The legislation would tighten sanctions and result in cutting Iran's oil exports by around 1 million barrels per day over the course of a year, with the goal of ending all Iranian oil sales worldwide by 2015.
It provides for heavy penalties against businesses in third countries that do not find alternative supplies.
The sanctions are meant to convince Iran to halt its nuclear development program, which some, including the United States, believe is aimed at producing a nuclear weapon. Iran insists its nuclear program is purely for civilian purposes.
The Senate is due to consider the bill in September.
Before the House passed the bill, some Congressmen argued that the measure was badly timed, coming just ahead of Hassan Rohani's inauguration on August 4.
Rohani, a former nuclear negotiator, is seen by some as more moderate than his predecessor, Mahmud Ahmadinejad.
Democrat Jim McDermott, who voted against the bill, suggested that it could undermine U.S. efforts to resolve the nuclear issue through diplomacy.
"Experts and former military officers including the commander in chief of the Central Command warn that more sanctions, right now, will undercut the new president and his pledged plan of moderation," he said.
"It gives ammunition to the hard-liners who will operate against him, so the timing of this bill could not be worse from a foreign-policy perspective."
Others, like Republican Ted Poe, maintained that the real power in Iran rests with Supreme Leader Aytollah Ali Khamenei, not the president.
"This new so-called president of Iran is no different than Ahmadinejad. Rohani is no moderate, he's just slick. He has lied to the United States in the past and don't be deceived, he is not even in charge of Iran," Poe said.
"The ayatollah is in charge and the ayatollah picked all of the candidates running for president. The ayatollah is still calling the shots, and is determined to get nuclear weapons and eliminate Israel and the United States."
Iran's top oil consumers include China, India, Japan, and South Korea. For countries that do not stop buying Iranian oil, the U.S. legislation calls for the blacklisting of banks and companies involved.
Analysts say the measure risks pushing up world oil prices, putting further strains on the global economy.
White House officials have said that the Obama administration is not opposed to new sanctions in principle, but wants to give diplomacy a chance.
The Nuclear Iran Prevention Act would further limit the Iranian government's access to foreign currency reserves, and would penalize companies who help Iran circumvent international sanctions in other industrial sectors.
It also blacklists any business in Iran's mining and construction sector.
With reporting by Reuters and AFP