NATO has officially ended its combat mission in Afghanistan marking the end of 13-year-old war against the Taliban regime. 

A ceremony was held in Kabul on Sunday on this occasion. This ceremony marked the end of longest war in American history. 

The withdrawal was formally announced at a low-key ceremony in Kabul by International Security Assistance Force. 

The combat mission started in 2001 --- a month after New York's world trade towers were downed in a terror strike. 

NATO forces joined hands to dislodge the Taliban rule which had turned Afghanistan into a safe haven for terrorists. 

Around 130,000 troops from 50 nations were present in the mission during its peak in 2011. 

Close to 3500 soldiers lost their lives in the 13-year-long conflict that devastated the core Al-Qaeda leadership. 

Afghanistan acknowledged the efforts of the international force on this occasion. 

"On behalf of President Ghani and the people of Afghanistan I would like to express our deepest gratitude for the NATO coalition's efforts and sacrifices in Afghanistan since 2001, the cost of our struggle has been enormous." 

More than 2000 US soldiers were among the military casualties in Afghanistan. 

Remembering the sacrifice of his country's soldiers, US president Barack Obama called the ceremony a milestone for America. 

However, he warned that Afghanistan remains a dangerous place, and the Afghan people and their security forces continue to make tremendous sacrifices in defense of their country. 

Despite the formal exit of NATO forces, there will be US military presence in Afghanistan for few more years.

The US will leave a residual force of close to 12,000 troops behind to help provide support to Afghan security forces. 

The soldiers will be part of a mission named 'Resolute Support' which will focus on training Afghan security forces as the country still remains in a perilous position. 

It is not necessarily a mission accomplished for the US but more a mission continued in the war-torn country.