US President Donald Trump speaks after being sworn in as the 45th president of the United States in Washington 20 January 2017 Reuters/Kevin Lamarque

President Donald Trump has issued a proclamation that the day of his inauguration will be known officially as the National Day of Patriotic Devotion.

The proclamation was among three of the first documents that Trump signed on Inauguration Day, according to his press secretary Sean Spicer.

Others included a waiver of a rule that would allow retired General James Mattis to become the Trump administration's secretary of defence, and official Senate documents for Trump's cabinet nominations, as well as an executive order stating that lawmakers can begin dismantling the Affordable Care Act known as Obamacare.

The full text of the proclamation was published Tuesday 24 January in the Federal Register after being filed the day before.

When he was first inaugurated on 20 January 2009, President Barack Obama signed a similar document calling his Inauguration Day a "National Day of Renewal and Reconciliation."

Obama's proclamation said he was "humbled by the responsibility placed upon my shoulders, renewed by the courage and decency of the American people, and fortified by my faith in an awesome God."

"We are in the midst of a season of trial. Our Nation is being tested," Obama wrote, "and our people know great uncertainty. Yet the story of America is one of renewal in the face of adversity, reconciliation in a time of discord, and we know that there is a purpose for everything under heaven."

It's not unusual for presidents to proclaim these one-time holidays through executive orders, but only Congress can create annual federal holidays.

"A new national pride stirs the American soul and inspires the American heart," reads Trump's proclamation.

"We are one people, united by a common destiny and a shared purpose," it says. "There is no freedom where the people do not believe in it; no law where the people do not follow it; and no peace where the people do not pray for it."