Islamist organisation Hizb ut-Tahrir is holding a major international conference in Indonesia. But what are its views and why do some people view it with suspicion?
What is Hizb ut-Tahrir?
Hizb ut-Tahrir (HT) which translates as the "party of liberation" is a radical political organisation which has members in the Muslim world and in countries with significant Muslims population. It was formed half a century ago in Jerusalem by an Islamic jurist, Taqiuddin an-Nabhani.
Typically, members meet in small private study circles but in open societies such as the UK it also organises rallies and conferences and engages with the media.
What does it believe?
In short, HT wants to establish an Islamic state across the Middle East - something known as a "Caliphate, or Khilafah in Arabic. The organisation regards the Caliphate as the ideal form of government which emerged from Islam 1,400 years ago because it is government according to the laws of God, as set out in the Koran, rather than by laws designed by man.
The organisation believes that the system practised by the Prophet Mohammad during the first years of Islam is applicable to all of the Muslim "umma" in Muslim lands. HT regards Islam as an entire system for life - in other words there should be no separation between religion and politics.
Where is it most active?
It's difficult to know how many members an international organisation like HT has as it does not reveal the numbers.
But it is active across the Middle East, central and south-east Asia and, increasingly, Europe.
It has been most active in central Asia and is banned in many of those countries. Members face persecution, jail or worse - although the same treatment is often meted out to members of other political movements in these countries.
In the UK its support is thought to be the strongest among non-Muslim countries as the organisation is well organised on university campuses. A conference in August 2007 attracted some 2,000 people, although not all of these were actual members. Indonesia is the site for its annual global conference in 2007 with a large stadium hired for the event.
Where does it stand on democracy?
It totally opposes it, saying that participating in a Western-style democracy is incompatible with the goal of establishing an Islamic state because it means voting for parties that do not subscribe to God's law. It does say, however, that such an Islamic state would include provisions for voting in an Islamic context.
So has it got a violent agenda?
HT says that it does not advocate violence and is not a "conveyor belt" towards terrorism. Many experts agree that it is a purely ideological movement focused on its intellectual messages.
UK former Prime Minister Tony Blair said he would ban HT - but after two official reviews no action was taken.
If there is no evidence of violence, what exactly is the complaint?
HT's worldview is shared by other Islamist organisations, some of whom believe that violence is an answer. In the UK, critics - including a former member who wrote a book about his experiences - argue that it plays a part in radicalising young men to believe that they cannot be simultaneously British and Muslim.
Some of these young men, argue critics, will ultimately find a violent path and take it - hence the "conveyor belt" accusation. Germany banned the organisation after naming it as a radical Islamist movement with anti-Semitic views.
So is it anti-Semitic?
Again, HT insists not. However, its views on Israel are considered by opponents to be offensive. It says that Israel was formed by taking other people's land by force.
Therefore, HT says that Islam is "in conflict with Israelis - not in their capacity as Jews who historically lived alongside Muslims in peace and security for centuries - but in their capacity as occupiers and aggressors."
The World Jewish Congress has accused HT of aggressively propagating anti-Semitic ideas, saying that it trades language, insults and accusations against Jews seen in other Islamist literature.