New Delhi, September 11: President of the United States of America Donald Trump on Monday led a moment of silence at the White House to mark the 16th anniversary of the September 11 terrorist attacks in New York, Washington and Pennsylvania. The White House commemoration took place at the same time relatives of victims, survivors, rescuers and others gathered at New York’s 9/11 memorial on Monday at 08.46 (local time) to mark the exact time the first plane struck the World Trade Centre’s North Tower.

Over 2,500 people were killed after hijackers crashed planes into New York’s World Trade Centre, the Pentagon and a rural Pennsylvania field in 2001. The attacks were directed by Al Qaeda leader Osama bin Laden.

Vice President Mike Pence travelled to Shanksville, Pennsylvania, where one of the four hijacked jetliners crashed after passengers overpowered the hijackers. He was also scheduled to speak at the rural site of the crash. He and his wife will reportedly tour the Flight 93 National Memorial nearby.

Remembering 9/11: How the events unfolded

• 7:59 am- 9:02 am

American Airlines Flight 11 with 92 people aboard took off from Boston’s Logan International Airport to Los Angeles. Another flight, United Airlines Flight 175 with 65 people aboard took off from Boston to Los Angeles. Soon, flight attendants aboard Flight 11 alerted ground personnel that the plane has been hijacked, following which the airlines notified the FBI.

The third plane, an American Airlines Flight 77,  took off from Dulles International Airport outside of Washington, D.C,  also to Los Angeles with 64 people aboard.

Reportedly, hijacker Mohammed Atta made the first of two accidental transmissions from Flight 11 to ground control. Following which the Federal Aviation Administration (FAA) alerted North American Aerospace Defense Command (NORAD)’s Northeast Air Defense Sector (NEADS) about the suspected incident of the hijacking of Flight 11. In response, NEADS scrambled two fighter planes located at Cape Cod’s Otis Air National Guard Base to locate and tail Flight 11. Before the two fighter planes took off, Flight 11 crashed into the North Tower. Mohammed Atta and the other hijackers aboard American Airlines Flight 11 crash the plane into floors 93-99 of the North Tower of the World Trade Center, killing everyone on board and hundreds inside the building.

Moments later the NYPD and FDNY forces dispatched units to the World Trade Center, while Port Authority Police Department officers on site began evacuation of the North Tower. While initially tenants of the WTC’s South Tower were ordered to remain in the building, soon Port Authority officials broadcast orders to evacuate both towers via the public address system.

. 9:03 am – 11 am

The hijackers crashed the United Airlines Flight 175 into floors 75-85 of the WTC’s South Tower which killed everyone on board and hundreds inside the building. Immediately, the FAA banned all takeoffs of flights going to New York City or through the airspace around the city. The Port Authority also closed all bridges and tunnels in the New York City area.

The FAA notified NEADS of the suspected hijacking of Flight 77 after a few passengers and crew aboard were able to alert family members on the ground. And it was then that President George W. Bush, who was attending a school event, announced about the attack and called it an ‘apparent terrorist attack’.

The Hijackers on Flight 77 crashed the plane into the western façade of the Pentagon in Washington, D.C., which claimed lives of 59 aboard the plane and 125 military and civilian personnel inside the building.

United Airlines Flight 93, a Boeing 757 with 44 people aboard, took off from Newark International Airport en route to San Francisco. It had been scheduled to depart at 8:00 am, around the time of the other hijacked flights. The FAA immediately grounded all flights over or bound for the continental United States. Over 3,300 commercial flights and 1,200 private planes were then guided to airports in Canada and the United States over the next two-and-a-half hours. This was followed by an evacuation of the White House and U.S. Capitol building along with other high-profile buildings, landmarks and public spaces. And the South Tower of the World Trade Center finally collapsed.

As passengers and crew members onboard the hijacked Flight 93 contacted friends and family, they learned about the attacks in New York and Washington and then made an attempt to retake the plane. The hijackers then deliberately crashed the plane into a field in Somerset County, Pennsylvania, killing all the 40 passengers and crew aboard.

At around 10:30 am, the World Trade Center’s North Tower collapses, nearly two hours after being struck by the airplane.

What followed after this was basically announcements, and President Bush address to the nation, in which he called the attacks “evil, despicable acts of terror” and urged the people to “stand together to win the war against terrorism.”

Later it was learned that the mastermind of the attacks was Al-Qaeda leader Osama bin Laden and soon he was declared as the most wanted criminal. After years of pursuing links to find Osama, who was in hiding and continued to issue threats to the US among others, in a covert mission, on May 2, 2011, he was located and killed in Pakistan by Navy SEAL teams of the U.S. Naval Special Warfare Development Group.