Anti-government protests are taking place in Tehran and other cities after Iranian authorities "lied" about a Ukrainian international airliner being "mistakenly" shot down.
Several protesters were heard chanting slogans against the country's leadership.
But how strong is this anti-government movement inside Iran? How strong is the opposition there? What do the agitators want?
In recent days, ordinary people have taken to the streets in Tehran, Iran, and several other cities, such as Isfahan, to protest the deaths of passengers in a plane crash
Most of them are mainly university students and middle class people.
At first they blamed the authorities for not telling the truth about the actual incident. But protesters also chanted slogans against the country's supreme leader, Ayatollah Khamenei, and Islamic rule.
The BBC's Rana Rahimpur says "many of the protesters know the victims of the plane crash. Since most of them were students and could afford to travel abroad."
There is no indication that the protests revolved around a specific personality.
"It's hard to say that there is anyone around whom people can now unite," said Fatemeh Shams, an Iranian professor at the University of Pennsylvania.
Iran's political system allows elections, but political parties have to operate within the strict boundaries of the Islamic Republic.
In the 2016 parliamentary elections, Iran's Guardian Council disqualified about half the candidates. E
The Guardian Council oversees whether the candidates are keeping their promises regarding the Islamic system of the run.
And thousands of potential candidates have been disqualified for next month's parliamentary elections, including 90 current lawmakers.
Candidates from anti-Islamic republican groups who want to completely change the existing system are not allowed to run in the elections.
The Guardian Council can also impose sanctions on any presidential candidate and veto any law passed by parliament if it does not appear to be in line with Iran's constitution and Islamic law.
Ayatollah Khamenei, who is at the top of Iran's political structure, appoints half of its members.
This Supreme Leader controls the armed forces and decides on issues related to security, defense and major foreign policy.
So in reality, Iran's president and parliament - although they are in favor of change - have limited power.
There are also movements for greater autonomy for ethnic minorities inside Iran, such as the Kurds, Arabs, Baluchis and Azerbaijanis.
These opposition groups include the Iranian Kurdistan Democratic Party - an armed group that has been fighting the Iranian state for decades.
A reformist movement has been going on in Iran for many years, with former President Mohammad Khatami seen as its main figure.
During his tenure in power from 1996 to 2005, Mr Khatami introduced some social and economic reforms and made some proposals to the West.
Larger changes were blocked due to conservative interests, and Mr Khatami was cornered by limiting his movements and appearances to the media.
In 2009, the country faced a major challenge following the victory of hardline Mahmoud Ahmadinejad in a controversial presidential election.
Defeated Mir Hossein Mousavi and Mehdi Karroubi challenged the outcome of the vote and became the leader of a party known as the Green Movement.
Millions of people took to the streets to demand re-election, but Ayatollah Khamenei insisted the election was fair.
Violence erupted against protesters that year, and several opposition supporters were reported killed.
Many of the opposition's top figures were detained. Mr Mousavi and Mr Karroubi are still under house arrest a decade later.
Recently, there have been protests in late 2016 and early 2017 over the deteriorating economic situation.
Unemployment is on the rise in some parts of the country, angering young people.
The upper middle class also joined the protest against the government of President Hassan Rouhani, who is considered liberal.
Protesters chanted slogans against the country's leaders, calling for the restoration of the monarchy, which collapsed in 1989
Amir Kabir gathered outside the university and demanded the resignation of the officials who took refuge in lies.
More than 304 people were killed in the violence, according to Amnesty International, but a Reuters report put the death toll at 1,500.
Iranian authorities have rejected two figures. The country was without internet connection for five consecutive days. As a result, communication between the whole country was cut off.
A feature of the recent protests is that they were often without leadership, and problems such as inflation, unemployment and inequality angered the grassroots.
However, despite the intense instability, the government has managed to keep them under control. Because they have taken repressive measures against the opposition as well as imposing strict restrictions.