Newsbeat's guide to... Iran
Iran is again under pressure over its controversial nuclear programme after the UN said the country's scientists had enriched uranium to 20%.
Uranium is an element that can be used to make nuclear weapons. It can also be used to produce energy at nuclear power stations.
Experts say getting the uranium to 20% is an important step in making it good enough to be used in a bomb or missile.
Iran says its use of uranium is for peaceful purposes, but many countries say they don't believe it.
UK Foreign Secretary William Hague says Iran's actions are "provocative" and America and France want the enrichment to stop.
With a block on Iranian oil set to be approved, the country is now threatening to close down a major shipping route.
What is life like in Iran?
The country has a young population, with an average age of about 27.
It's governed by Mahmoud Ahmadinejad, a very traditional, conservative president.
He was controversially re-elected in 2009 but political opponents claimed votes had been rigged.
Protests at the result led to more than 30 deaths.
The media in the country is relatively free and there are more than 32 million internet users.
A very important figure in Iran is its Supreme Leader, an Islamic religious figure called Ayatollah Ali Khamenei.
He has a big influence of what laws are passed and also chooses the country's top judge, military leaders, and the head of radio and TV.
What action is being taken against Iran?
Restrictions on dealing with Iran have been around for a number of years.
Some of the restrictions aim to hurt the country's economy, others make it harder for Iran to get hold of nuclear equipment.
The UN banned the sale of heavy weaponry and nuclear-related technology when the country failed to co-operate with inspections of its nuclear sites.
The EU has frozen the assets of people it says are helping Iran with its nuclear programme and stopped them from entering the EU.
It's also likely to approve a block on oil imports from Iran later this month.
That could hit the country hard - it's one of the biggest oil producers in the world and the EU buys more than 500,000 barrels from Iran every day.
British banks have also been told by the government not to deal with financial institutions in Iran.
America also bans almost all trade with Iran, apart from things like medical equipment.
Is military action a possibility?
Despite the tensions, it's unlikely at the moment. The hope is that sanctions will eventually persuade Iran to cut back its nuclear programme.
However, the US and Israel have not ruled out the possibility.
If they did attack one of the sites - like the facility in Qom that was uncovered by Western Intelligence in 2009 - they might have a difficult job.
It's built underground and protected by the armed forces.
Experts say it could probably resist most bomb attacks.
What does Iran say about it all?
Its president, Mahmoud Ahmadinejad, insists the country's nuclear ambitions are all about nuclear fuel, research, and making material to treat cancer.
The UN's nuclear watchdog, the IAEA, disagrees and says lots of Iran's research is "specific to nuclear weapons".
Iran is angry about the restrictions imposed on it and is threatening to block the Strait of Hormuz, a shipping route that carries a fifth of the world's oil.