As President Donald Trump pushes to end the US involvement in Afghanistan, where 14,000 US troops are still stationed, here is a timeline of its involvement since 2001.

- 'War on terror' -

On October 7, 2001 -- less than a month after the September 11 attacks that killed around 3,000 people in New York and Washington -- President George W. Bush launches operation "Enduring Freedom" in Afghanistan.

The country's fundamentalist Taliban regime had been sheltering Osama bin Laden and his Al-Qaeda movement, accused of the attacks.

The operation opens a military front in the US "war on terrorism".

Within weeks US-led forces overthrow the Taliban, in power since 1996.

Besides carrying out air strikes, Washington also lends support to the Afghan Northern Alliance fighting the Taliban, contributing paramilitary teams from the CIA and special forces.

About 1,000 American soldiers are on the ground by November 2001, rising to 10,000 the year after.

- Forgotten war -

US attention is diverted from Afghanistan when US forces invade Iraq in 2003 to oust dictator Saddam Hussein, accused of harbouring weapons of mass destruction.

In 2004 Afghanistan holds its first presidential election based on universal suffrage, with Hamid Karzai winning 55 percent of the vote.

The Taliban and other Islamist outfits regroup in their strongholds in southern and eastern Afghanistan, from where they can easily travel between their bases in Pakistan's tribal zones, and launch an insurgency.

In 2008 the US command in Afghanistan calls for more manpower. Bush sends additional soldiers and by mid-2008 about 48,500 US troops are deployed.

- Peak of 100,000 troops -

In 2009 Barack Obama -- elected president on campaign promises to end the Iraq and Afghanistan wars -- boosts the US deployment to around 68,000. In December he raises it to around 100,000.

The objective is to put brakes on the growing Taliban insurgency and to strengthen Afghan institutions.

- Bin Laden killed -

Bin Laden is killed on May 2, 2011 in an US special forces operation in Pakistan.

- Combat operations end -

On December 31, 2014 the NATO alliance ends its combat mission in Afghanistan. But, under agreements reached a few months earlier, 12,500 foreign soldiers -- of which 9,800 are American -- remain to train Afghan troops and conduct anti-terrorist operations.

Security in Afghanistan degenerates as the Taliban's insurgency spreads, with the Islamic State (IS) group also becoming active in early 2015.

In July 2016 Obama slows the planned pace of withdrawal of US troops, saying 8,400 will remain into 2017.

- MSF clinic bombed -

In October 2015, amid intense fighting, a US airstrike hits a Medecins Sans Frontieres (Doctors Without Borders) hospital in northern Kunduz province, killing 42 people, including 24 patients and 14 members of the NGO.

- Mega bomb against IS -

In April 2017 the US military drops the largest non-nuclear bomb it has ever used in combat on an IS network of tunnels and caves in eastern Afghanistan. Afghan officials say it killed more than 90 jihadists.

- 'Stalemate' -

In February 2017 the US general commanding the NATO force, John Nicholson, warns that he needs more troops, telling Congress: "I believe we're in a stalemate."

In August Trump scraps any timetables for a US pullout and re-commits thousands more soldiers.

However deadly attacks multiply. The United States steps up air strikes dramatically, dropping 6,823 bombs in the first 11 months of 2018 -- five times the total in 2016. Civilian casualties also rise, the UN warns.

- Talks -

In mid-2018 Washington and Taliban representatives discreetly open talks in Doha.

In November 2018 Trump says the United States is in negotiations regarding Afghanistan and, "We are talking about peace."

The following month, officials say he plans to withdraw half of the 14,000 US soldiers in the country. On Monday, Acting Defense Secretary Patrick Shanahan says he has received no orders to begin a drawdown yet.

January 2019 sees unprecedented marathon negotiations with the militants in Doha, with both sides touting "progress" and US special envoy Zalmay Khalilzad spreading a "draft framework" -- though he warns that "nothing is agreed to until everything is agreed to".

In early February Khalilzad, says the United States is hoping Afghanistan can strike a peace agreement including the Taliban before elections due in July.