The situation in Iran has reached the point of no return. The opposition has been calling for weeks for the downfall of the Islamic Republic and the removal from power of the supreme leader, Ayatollah Ali Khamenei. His own supporters have demanded the "harshest possible punishment for the instigators of unrest". Judging by the video footage and photos distributed via the internet, despite the brutal clampdown of the last six months the opposition does not appear frightened. The demonstrators are directly confronting the police and security forces. Many police officers have been injured in the clashes of the last two days together with scores of opposition injuries and eight deaths on Sunday – Ashura – a day on which in Islamic tradition no blood is to be spilled. Some of the pictures of those killed on Sunday are as gruesome as last summer's images of Neda Agha Soltan.

Different layers of the opposition, the reformist Islamists as well as the more modern, possibly secular young activists and academics – and artists, musicians and journalists – have been enraged over the past few weeks. Students – always at the forefront of democratisation movements in Iran – were not allowed to mark their national day on 16 Azar (7 December); high-ranking reformist ayatollahs in Qom and Isfahan were not allowed to mourn the death of the highly respected Grand Ayatollah Hossein Ali Montazeri. Several ayatollahs and leading opposition figures who have spoken out in defence of human rights, the right to demonstrations, and for a free media, have been threatened with losing their positions, and accused of "collaboration with western conspiracy". Hundreds of high-ranking opposition figures were arrested on Sunday and Monday, and many who are in detention received long prison sentences.

However, despite their unprecedented techniques of distributing information and mobilising support, the opposition still lacks a clear statement as to where it is going and what it would do were it to topple the regime. It also lacks a leader accepted by all. Activists argue that if they did have such clarity the entire machinery of the state would ensure their leadership was obliterated. And it is true that the military arm of the regime is killing and arresting at random.

It is also true that Khamenei no longer has any of his seasoned advisers – such as former presidents Hashemi Rafsanjani and Mohammad Khatami, or the former speaker of the parliament Mehdi Karoubi. He sidelined them all when supporting Mahmoud Ahmadinejad for the presidential elections. Over the past six months the supreme leader has also lost crucial links with the reformist ayatollahs and clergy in the holy cities of Qom, Isfahan and Mashhad.

The leader is now surrounded by the hardline clergy, right of centre politicians, Revolutionary Guards and Basij militia, who are calling for direct confrontation. This can only lead to further bloodshed. The opposition is now calling for more strikes and attacks at important centres of power such as the state TV, where clashes took place yesterday. And February sees the 31st anniversary of the Islamic Republic. There is talk of a military coup by the Revolutionary Guards if the situation does not settle down.

Iran is facing a long period of political instability; and with increasing tensions in neighbouring Pakistan, plus the volatile situation in Afghanistan and Iraq, regional security appears more precarious than any time in the recent past.