ABC News’ Tahman Bradley Reports:

President Obama and his wife Michelle Obama today paid respect to 9/11 victims by visiting the North Memorial Pool in the footprint of the spot where the north tower of the World Trade Center stood on this 10th anniversary of the terrorist attack.

The two observed a moment of silence commemorating the exact minute the first airplane crashed into the north tower, after which President Obama read a passage from Psalm 46.

“God is our refuge and strength, a very present help in trouble,” the scripture says.

The Obamas were joined by former President George W. Bush and Laura Bush. The two couples walked along the edge of the pool and observed the names victims of 9/11 and the 1993 WTC bombing inscribed around the pools. The couples then greeted some families of the 9/11 victims.

Presidents Obama and Bush also exchanged pleasantries with former New York Mayor Rudy Giuliani, former New York Gov. George Pataki, New York Gov. Andrew Cuomo, New Jersey Gov. Chris Christie, New York Mayor Michael Bloomberg and other dignities on hand at the memorial.

This was President Obama’s second trip to the memorial site after first visiting back in May.