The New York Stock Exchange (NYSE) marked a moment of silence on Friday, the last trading day before the 20th anniversary of the attacks on Sept. 11, when two airliners crashed into the twin towers at New York's World Trade Center.

The moment occurred at 9:03 a.m. EST (1403 GMT), the time the second plane struck the South Tower in 2001. More than 2,600 at the World Trade Center were killed, as well as 125 people who died at the Pentagon and 265 on the four airliners involved in all the attacks.

The U.S. national anthem was also sung on the floor of the stock exchange.

Traders, first responders and family members of the fallen participated in the commemoration.