Three.

Killing of Tehran's top nuclear scientist Let's look at the deal and how close Iran could be to producing a nuclear bomb.

Three Accord is one of the most intrusive nuclear verification regimes imposed on any nation.

The result is a lasting, comprehensive deal that prevents Iran from obtaining a nuclear weapon while allowing it to access peaceful energy.

It has one objective to extend how long it would take Tehran to get enough fissile material together to make a bomb known as the breakout time.

Iran maintains that it has never sought nuclear weapons and never would and says its nuclear work only has civilian aims.

But Tehran began breaching the deals curbs last year in a step by step response to Trump's withdrawal from the deal in May 2018 on the reimposition of US sanctions, we cannot allow the world's leading sponsor of terrorism to possess the planet's most dangerous weapons.

Iran exceeded the limits of how much enriched uranium it can stockpile the enrichment level.

It's refined at on the type of centrifuges and sites it uses for the process.

Tehran is still cooperating with the U.

N agency that police is the deal, which in turn says Iran isn't moving ahead with nuclear work as fast as it could, which is are also going to be operating.

But the breaches mean the break out time has been shortened.

So how close could Iran be toe having a bomb?

Estimates of the breakout time vary.

The aim of the deal was to increase it from around 2 to 3 months to at least a year.

But many experts say that's conservative on Iran would in reality need longer.

Then, even if enough fissile material was accumulated, it would need to actually assemble a bomb on probably one small enough to be carried by its ballistic missiles.

It's unclear how long that would take, but the stockpiling of fissile material is widely seen as the biggest hurdle in producing a weapon.

Supporters of the deal are hoping for a change in US policy once President elect Joe Biden takes office.