WASHINGTON: President Barack Obama said Thursday that Al-Qaeda tried to “terrorize” Americans with the September 11 attacks in 2001, but was no match for US resilience and was now on the path to defeat.

In an opinion piece for USA Today, Obama called on Americans to regain the sense of national unity that prevailed in the aftermath of the strikes on New York and Washington in 2001 which killed nearly 3,000 people.

“The perpetrators of those attacks wanted to terrorize us, but they are no match for our resilience,” Obama wrote.

“Today, our country is more secure and our enemies are weaker. Yet while we have delivered justice to Osama bin Laden and put Al-Qaeda on the path to defeat, we must never waver in the task of protecting our nation.”

At a time of deep partisan disagreement in Washington and economic dislocation across the country, Obama also called on Americans to renew the “common purpose that stirred in our hearts 10 years ago.”

”As a nation, we face difficult challenges, and as citizens in a democratic society we engage in vigorous debates about the future,” Obama said, likely previewing the theme of his remarks at September 11 10th anniversary ceremonies on Sunday.

“But as we do, let's never forget the lesson we learned anew 10 years ago, that our differences pale beside what unites us.”

Obama will start his day on Sunday in New York at the “Ground Zero” site of the World Trade Center twin towers felled by hijacked airliners turned into fuel-laden flying bombs.

He then moves onto Shanksville, Pennsylvania, where a seized civilian jet believed to be headed to Washington, was downed in a revolt against the hijackers by passengers.

Obama is also due to visit the Pentagon, which was hit by another plane and to attend a “Concert of Hope” at the John F. Kennedy Center for the Performing Arts in Washington.

The evening event was moved from Washington's National Cathedral after a huge crane being used to repair damage from an earthquake last month fell over.