Speaking at a ceremony marking the 18th anniversary of the 9/11 attacks, Trump said that over "the last four days" U.S. forces have "hit our enemy harder than they have ever been hit before and that will continue". Trump cancelled a "secret" summit with Taliban leaders and his Afghan counterpart last week after the insurgent group claimed responsibility for a deadly attack in Kabul that killed an American soldier and 11 others, dealing a body blow to protracted negotiations that were nearing a peace deal to end America's longest war.
It's unclear if the U.S. -Taliban talks will resume, but Trump has said he wants to withdraw about 5,000 of the 14,000 U.S. service members still in Afghanistan.
Less than a month after the terror attacks, Bush announced on October 7, 2001, that USA and British troops had begun striking Afghanistan for harboring the al-Qaida terrorists blamed for 9/11.
US President Donald Trump has remembered the thousands of people killed 18 years ago in the 9/11 attacks and warned that any other terrorist who comes to the United States would be met with a force "the likes of which the United States has never used before". Warning terrorist groups of any such misadventure in future, Trump said, "And I'm not even talking about nuclear power. They will have never seen anything like what will happen to them".
The announcement angered some, coming so close to the September 11, 2001 anniversary. Silences were also held at the times the 100-storey-plus skyscrapers fell.
In what has become an annual tradition, relatives began reading out the long list of those who were killed, saying a few words about each victim, in a ceremony that took nearly four hours. Her boyfriend Robert Edward Evans, was a member of Engine 33.
Bagpipes played as police officers walked into the ceremony carrying the United States flag before the U.S. national anthem was played. "The last time hearing those precious words, 'I love you, '" said Trump, who began the day observing a moment of silence on the South Lawn with first lady Melania Trump and White House staff.
At the National September 11 Memorial, Mary Novoty, of NY holds a picture of her son, Brian, who was killed at the World Trade Centre.
Secretary-General Antonio Guterres's Special Representative for Afghanistan, Tadamichi Yamamoto, said: "We still hear much anxiety expressed by Afghan citizens particularly in view of the Taliban's stated threat to disrupt the electoral process, especially by targeting civilians participating in the elections".
The US and the Taliban have for almost a year been attempting to negotiate a peace deal that would ensure the withdrawal of foreign troops in exchange for the movement's guarantee that the country will not become a safe haven for terrorists.
There were fears Mr Trump's cancellation of the negotiations could bring more carnage in Afghanistan.
Speaking to Dana Perino on Wednesday, Theissen gave credit to ousted national security adviser John Bolton for his reported opposition to inviting the Taliban.