"I'm here to announce the completion of our withdrawal from Afghanistan."

The words of US General Kenneth McKenzie at a Pentagon briefing officially marking the end of America's longest war.

After 20 years, thousands of lives lost and trillions of dollars spent, the majority of Americans wanted to see an end to the conflict but now that it is over, there is unlikely to be much celebration.

Instead, there will be plenty of reflection on the chaotic evacuation mission over the last two weeks.

It began with scenes of desperation at Kabul Airport as thousands tried to flee.

On Thursday, a devastating bomb attack claimed the lives of at least 169 Afghans and 13 US service members.

That was the nightmare scenario for US President Joe Biden.

The reason he wanted to leave Afghanistan was to end the loss of life but in an instant, all hopes of a peaceful withdrawal were dashed and American blood had been spilt.

In a statement following the conclusion of the mission, Mr Biden paid tribute to those who lost their lives.

He also highlighted the success of the evacuation operation.

"The past 17 days have seen our troops execute the largest airlift in US history, evacuating over 120,000 US citizens, citizens of our allies, and Afghan allies of the United States. They have done it with unmatched courage, professionalism, and resolve."

"Now, our 20-year military presence in Afghanistan has ended," Mr Biden said.

The US mission in Afghanistan may be at an end, but a new era of fear and uncertainty is just beginning.

The United Nations Refugee Agency has warned of a looming humanitarian crisis.

Big questions remain over the safety of the US citizens and vulnerable Afghans who have been left behind.

What about the American military equipment and weaponry that is now in enemy hands?

And what of Afghanistan itself? Will it once again become a breeding ground for terrorism?

As America prepares to commemorate the 20th anniversary of the 11 September attacks next week, many will be wondering if the world has become a more dangerous place now that the Taliban is back in power.