Israel and Iran opened a new chapter in their long history of conflict when Israel launched a major attack with strikes early Friday that set off explosions in the Iranian capital of Tehran.Israel said it targeted nuclear and military facilities.

Iran was largely cut off from the outside world on Friday after authorities blacked out the internet to curb growing unrest, and videos showed buildings aflame in anti-government protests raging in cities across the country.

What began two weeks ago as a demonstration against an economic crisis has become a broader antigovernment movement, in cities and towns across Iran.Iran’s authoritarian government has responded with violent repression.