Iran’s feuding top clerics
As Iranians return to work this week after the new year holiday, one talking point is likely to be the serious split that has emerged among the country's top leaders.
People are used to clashes between moderates and hardliners, and also to tensions between elected presidents trying to implement reform and a conservative establishment resistant to change.
But last week, a very public feud opened up between two of the country's most powerful men - the Supreme Leader, Ayatollah Khamenei, and the former president, Ali Akbar Hashemi Rafsanjani, once a close ally but now an increasingly bitter opponent.
It is a dispute that raises fundamental questions about what kind of a country the Islamic Republic will be in coming years.
The spat began with a tweet sent last week from an account associated with Mr Rafsanjani calling for dialogue and not confrontation with the international community.
"Tomorrow's world is a world of dialogue, not missiles," the tweet said.
Mr Rafsanjani, who heads the influential Expediency Council is a strong supporter of the moderate president, Hassan Rouhani.
The recent victory of both men and their supporters in nationwide elections has put Mr Rafsanjani in a strong position and he's used it to be even more outspoken in his criticism of hard-line opponents.
The Supreme Leader, however, clearly saw the missile tweet as a step too far, and fired off a furious and unusually direct riposte.
Those who say Iran's future lies in negotiations rather than missiles are wrong, Mr Khamenei said.
Iranians who make this argument are either ignorant or traitors, he said.
This line was then picked up and repeated by imams leading Friday prayers.
At mosques across the country, prayer leaders denounced treacherous views and said those who espoused them should be sacked.
They didn't mention Mr Rafsanjani by name, but no-one was in any doubt who they were talking about.
In some countries such a sustained attack would signal that an official was about to lose his job, if not his liberty, but in Iran things are more complicated.
Disagreements between top officials have always been a part of political life in the Islamic Republic.
They're often referred to as "family disputes", which means they are tolerated up to a point.
One good example is the Supreme Leader, Ayatollah Khamenei himself. He had a notoriously bad relationship with the founding father of the Islamic Republic, Ayatollah Khomeini, when Mr Khamenei was Iran's president in the 1980s.
The tipping point in such disputes usually comes when someone is no longer seen as part of the family.
Mir Hossein Mousavi, for example, was a former prime minister and key insider, but he's spent the last five years under house arrest after galvanising opposition to Mahmoud Ahmadinejad in the disputed 2009 presidential election.
Mr Rafsanjani is still a politician to be reckoned with, but in a sign of just how much the dispute has unnerved him, one week on, he suddenly issued a retraction of the tweet that caused all the fuss.
It was a comment made seven years ago in an interview with a Dutch film company, he said, and it had been taken completely out of context.
He expressed regret at what he called the "distortion and truncation" of what he had said.
- Age: 81
- President for two successive terms from 1989-1997 and ran again in 2005, when he lost to Mahmoud Ahmadinejad in the second round
- Entered the race for the 2013 presidential election but was barred from standing
- Was head of the Assembly of Experts, the body which appoints the Supreme Leader, from 2007-2011
- Since 1989 has headed the Expediency Council, which adjudicates disputes over legislation
- Described as a "pragmatic conservative", he is part of the religious establishment, but is open to a broader range of views and has been more reflective on relations with the West
The war of words between the two men looks set to die down for now, but it clearly illustrates the deep tensions at the very heart of Iran's political system over the country's future.
Ayatollah Khamenei and Akbar Hashemi Rafsanjani are both getting old.
Both are starting to think about who will succeed them and how to protect their legacies - and their families - after they have gone.
- Age: 76
- President for two successive terms from 1981-1989
- Succeeded the original Supreme Leader and founder of the Islamic Republic of Iran, Ayatollah Khomeini, in 1989
- As Iran's spiritual leader and highest authority, he has the final say over all political affairs in Iran
- Widely regarded as the figurehead of the country's conservative establishment, he has repeatedly denounced the West and in particular the US
And the politicians and power brokers around them are starting to think very hard and with some trepidation about how this will affect them too.
There is a very great deal at stake, and all the more so because this is all happening at a time of change for Iran as the country begins to open up after the nuclear deal.
The appointment of a new Supreme Leader, when it comes, will be nothing short of an earthquake in Iran.
Whoever controls the office also controls very powerful unelected offices like the Guardian Council, which vets elections and thus wields huge influence over the political landscape.
Also at stake is control over the armed forces, judiciary, Expediency Council as well as Iran's gigantic charitable foundations which some estimate make up as much as 50% of the country's economy.
In the past, disputes between top officials were usually settled when the Supreme Leader intervened.
But this time it's the leader himself who is involved, and the dispute is about his own legacy.
Many Iranians are now looking back to 1989, when the founder of the Islamic Republic, Ayatollah Khomeini removed his formal successor, the highly respected Ayatollah Montazeri, from his position just a few months before his death.
The decision opened up a deep wound in the Iranian system that never really healed. Ayatollah Montazeri was eventually banished to house arrest in the city of Qom, but remained a focus for opposition and dissent in Iran until his death seven years ago.
Observers point out that in 1989 the Islamic Revolution was still strong and the system was able to recover and move on.
But the days of revolutionary fervour are long gone, and many Iranians now fear that the increasingly bitter dispute between their top clerics could plunge the country into chaos from which, three decades on, it would be much more difficult to recover.