BANGKOK (AP) — Armed with machetes and rifles, a ragtag band of insurgents comprised of members of Myanmar's Muslim Rohingya minority launched unprecedented attacks last week, triggering fighting with security forces that has left more than 100 people dead and forced at least 18,000 to flee into neighboring Bangladesh.

Here's a closer look at the Arakan Rohingya Salvation Army, the group that claimed responsibility for the attacks:

THE ORIGINS OF ARSA:

The group was formed last year by Rohingya exiles living in Saudi Arabia, according to the International Crisis Group, which detailed ARSA's or...