Iranians are free to protest against the government but must not jeopardise security, President Hassan Rouhani has said after four days of demonstrations.

Speaking at a cabinet session, he acknowledged that there were problems that needed to be solved but warned that violence would not be tolerated.

The protests have been the biggest show of dissent since huge rallies in 2009.

There have been clashes in several cities, and Iran has restricted social networks used to organise protests.

The "temporary" restrictions on the apps Telegram and Instagram were imposed to "maintain tranquillity", state news agency Irib reports.