On Monday, thousands of people turned out for a protest in the Iranian capital Tehran.
They were protesting against the Iranian President, Mahmoud Ahmedinejad. At least seven people were killed in the rally. But what's happening in Iran to spark the trouble?
What are the protests about?
An election was held in Iran to decide the new president. Mahmoud Ahmedinejad, who was already in power, won the vote. But lots of people think the results were fixed.
Everyone thought it would be a closely fought contest, but the results showed Mr Ahmedinejad had won by a long way.
Opposition supporters say there were problems with the way the vote was counted. They claim lots of suspicious things happened, like ballot papers going missing.
Who is involved?
He's the current president, and a controversial figure. He's known for speaking out against America and Israel.
He says the election was free and fair and that the results stand. He even held a victory rally, which was well attended. He still has a lot of supporters, despite the protests.
Mir Houssein Mousavi
Mr Ahmedinejad's main rival. He says the results of the election are false and wants the whole election to be re-run.
Mir Houssein Mousavi
He and his supporters want to update some of Iran's policies so they are less confrontational with other countries and give Iranians a bit more freedom.
But he's in a bit of a difficult position because he can only get his supporters to protest so much without the chance that people could get hurt.
The Supreme Leader, Ayatollah Ali Khamenei
The country's most powerful figure. He holds this position for life.
Ayatollah Ali Khamenei
The Supreme Leader is in charge of lots of things, including the military and law courts as well as foreign and security policies.
He initially said Mr Ahmedinejad's win was fair, but now he's backing a call for an inquiry into the elections.
It's the Guardian Council - Iran's top legal group - that overseas the elections and is responsible for confirming whether they've been run by the rules.
The Guardian Council is made up of 12 people, some of whom are appointed by the Supreme Leader.
It says it will recount some of the votes where people think there has been cheating, but at the moment it says it won't cancel the votes.
What happens now?
The votes will be recounted, but that might not be enough to satisfy Mr Musavi's supporters. Lots of them think the way the voting was carried out, even before the count, was wrong.
There is also the danger of more violence, as the two rival groups hold rallies.
What is the reaction in the rest of the world?
Relations with Iran have been strained for a long time for many countries.
America is trying to rebuild its relationship with Iranian authorities.
American President Barack Obama has expressed concern about the violence there, but doesn't want to be seen to be trying to interfere in Iran's internal affairs.