The landmark nuclear deal forged between Iran and US-led world powers will "nuclearise" the Middle East, warned Sen. John McCain on Monday.

The Arizona senator, who ran and lost against President Barack Obama in the 2008 US presidential election, likewise said he also does not think Congress will approve the historical accord in the first round, wrote Newsmax.

"I think it's not going to get through the first round, as you know, but the President's already said he would veto and then the question is, are there sufficient votes to override a veto?" said McCain during MSNBC's "Morning Joe" program.

The Republican stalwart—who is part of a "No Nukes for Iran" tour with Republican presidential candidate Lindsey Graham and former Senator Joe Lieberman, which they conceived to discourage lawmakers from voting for the Iran nuclear pact—said he has talked to Middle East leaders who are "deeply concerned" about the agreement.

"They are moving in a direction of acquiring nuclear weapons, because they see this five-year, eight-year, 10-year window that they're going to have to, as Iran nuclearises, acquire nuclear weapons after 10 years," said the senator.

McCain also expressed fears about the pledge to lift economic sanctions against Iran, which has crippled the oil-producing country's economy, and in particular, Iranian General Qasem Soleimani.

"Gen. [Joseph] Dunford said that the copper-tipped IEDs [improvised explosive devices] killed at least 500 [in the] Army and Marines, and they're lifting the sanctions against him?" said McCain. "Someone's going to have to explain that to me."

The general's name is shown in an annex of the nuclear deal, despite his reported aid to Shiite militias who killed American soldiers in Iraq.

He also allegedly helped Syria's Bashar al-Assad.

"Soleimani is the guy that sent the copper-tipped IEDs into Iraq," said McCain, the head of the Senate Armed Services Committee.

At this point, however, "it's almost a take it or leave it" situation because it's an agreement, said McCain.

"But I also think we should be deeply concerned about continued Iranian aggression," said the lawmaker.

"They're now controlling four countries. We just found out when I was in Afghanistan over the Fourth of July. They're now providing weapons to the Taliban. Everywhere they're on the move, and they're succeeding and still the chief state sponsor of terror," McCain said.

He also said there was "very little doubt" from the Iranian side that the US wanted to hammer out the deal more than they did, "and that's how you got somehow an agreement on conventional weapons crept into this, when Secretary [John] Kerry had assured us time after time after time that this was only nuclear."

He added that there is "great concern" about how Iran intends to use the "tens of billions of dollars that are now going to be freed up."

"And, frankly, I'm on the side of Bibi [Israeli Prime Minister Benjamin Netanyahu]," said the senator, underlining his alliance with the Israeli leader.