Donald Trump took power as the 45th president of the United States on Friday and in an inaugural address that was a populist and nationalist rallying cry he pledged to end an "American carnage" of rusted factories and crime.

Striking a defiant tone, Trump said American workers have been devastated by the outsourcing of jobs abroad.

"From this day forward it's going to be only America first," the Republican told thousands of people gathered on the National Mall to see him take over from Democrat Barack Obama.