The word Donald Trump used more than any other in his inaugural speech

In a defiant tone reminiscent of the rallies that propelled him into office, President Donald J. Trump Friday vowed to put "America first."

American was also the word used more frequently than any other in his inaugural address to a crowd of cheering supporters.

"This American carnage stops right here and stops right now," he said. "Every decision on trade, on taxes, on immigration, on foreign affairs, will be made to benefit American workers and American families."

As Trump took office as the 45th U.S. president, Trump pledged to address the concerns of the American middle class, which he said has been devastated by the outsourcing of jobs abroad.

"From this moment on, it's going to be America First," the Republican told thousands of people gathered on the grounds of the National Mall as he took from Democrat Barack Obama.

With Obama and three other former presidents sitting nearby, Trump accused previous U.S. administrations of enriching Washington at the expense of struggling American families.

"The wealth of our middle class has been ripped from their homes and then redistributed across the entire world," he said.

—Reuters contributed to this report.