Lt Gen HR McMaster replaces Gen Michael Flynn, who was fired after just three weeks.
The militant group uses anger at corrupt officials to recruit new members, says a new report.
Uber has hired Barack Obama's attorney general Eric Holder to lead an investigation into claims of sexual harassment at the firm.
Rising risk of showdown between Trump and Iran
He calls Trump 'daddy' but who exactly is Milos Yiannopoulos?
Albino attack survivor lives in fear of more attacks
One policewoman's life on Mexico's southern border
Meet the woman who bakes the headlines
The Brazilian championing the rights of wheelchair tourists
8 groups forced into rival factions