Shafaqna (Shia International News Association) – The Grand Ayatollah Sistani answered some questions regarding Taqiyah.According to Shafaqna the questions and answers are as follows:
Question: What are the kinds of Taqiyah (dissimulation) and when is it obligatory?
Answer: There are different types of Taqiyah:
1) Taqiyah is done for safety reasons. For example, a person fears that he might be killed or harmed, if he does not observe Taqiyah. In this case, it is obligatory to observe Taqiyah.
2) Reconciliatory Taqiyah. This type of Taqiyah is done when a person intends to reconcile with the other side or when he intends to soften their hearts. This kind of Taqiyah is permissible but not obligatory.
3) Sometimes, Taqiyah may cause a more important obligation to be lost or missed, if so it is forbidden. For example, when I know that silence would cause oppression and infidelity to spread and will make people go astray, in such a situation it is not permissible to be silent and to dissimulate.
4) Sometimes, Taqiyah may lead to the death of an innocent person. If so, it is not permissible. It is therefore haram (forbidden) to kill another person to save your own life.
Source: Ayatollah Sistani