A timeline of more than 40 years of war in Afghanistan

The former Soviet Union marched into Afghanistan on Christmas Eve, 1979, claiming it was invited by the new Afghan communist leader, Babrak Karmal, and setting the country on a path of 40 years of seemingly endless wars and conflict.

After the Soviets left in humiliation, America was the next great power to wade in. Following the Sept. 11, 2001 terrorist attacks, the U.S. invaded to oust the Taliban regime, which had harbored al-Qaida leader Osama bin Laden.

After nearly 20 years, the U.S. is ending its war in Afghanistan, withdrawing the last American troops.

Left behind is the U.S.-allied government, riven by corruption and divisions, which must fend off advancing Taliban insurgents amid stalled peace talks. Many Afghans fear the next chapter will see their country plunge into chaos and inter-factional fighting among warlords.

Here is a timeline of some key dates in Afghanistan’s 40 years of wars:

Dec. 25, 1979 — Soviet Red Army crosses the Oxus River into Afghanistan. In neighboring Pakistan, Afghan mujahedeen, or Islamic holy warriors, are assembling, armed and financed by the U.S. for an anti-communist war. More than 8 million Afghans flee to Pakistan and Iran, the first of multiple waves of refugees over the decades.

1980s — CIA’s covert Operation Cyclone funnels weapons and money for the war through Pakistani dictator Mohammed Zia-ul Haq, who calls on Muslim countries to send volunteers to fight in Afghanistan. Bin Laden is among the thousands to volunteer.

1983 — President Ronald Reagan meets with mujahedeen leaders, calling them freedom fighters, at the White House.

September 1986 — The U.S. provides the mujahedeen with shoulder-held anti-aircraft Stinger missiles, which turns the course of the war. Soviets begin negotiating withdrawal.

Feb. 15, 1989 — The last Soviet soldier leaves Afghanistan, ending 10 years of occupation

April 1992 — Mujahedeen groups enter Kabul The fleeing Najibullah is stopped at the airport and put under house arrest at a U.N. compound.

1992-1996 — Power-sharing among the mujahedeen leaders falls apart and they spend four years fighting one another; much of Kabul is destroyed and nearly 50,000 people are killed.

1994 — The Taliban emerge in southern Kandahar, take over the province and set up a rule adhering to a strict interpretation of Islam.

Sept. 26, 1996 — The Taliban capture Kabul after sweeping across the country with hardly a fight; Northern Alliance forces retreat north toward the Panjshir Valley. The Taliban hang Najibullah and his brother.

1996-2001 — Though initially welcomed for ending the fighting, the Taliban rule with a heavy hand under Mullah Mohammed Omar, imposing strict Islamic edicts, denying women the right to work and girls the right to go to school. Punishments and executions are carried out in public.

March 2001 — The Taliban dynamite the world’s largest standing Buddha statues in Bamyan province, to global shock.

September 2001 — After 9/11 attacks, Washington gives Mullah Omar an ultimatum: hand over bin Laden and dismantle militant training camps or prepare to be attacked. The Taliban leader refuses.

Oct. 7, 2001 — A U.S.-led coalition launches an invasion of Afghanistan.

Nov. 13, 2001 — The Taliban flee Kabul for Kandahar as the U.S.-led coalition marches into the Afghan capital with the Northern Alliance.

Dec. 5, 2001 — The Bonn Agreement is signed in Germany, giving the majority of power to the Northern Alliance’s key players and strengthening the warlords who had ruled between 1992 and 1996. Hamid Karzai, an ethnic Pashtun like most Taliban, is named Afghanistan's president.

Dec. 7, 2001 — Mullah Omar leaves Kandahar and the Taliban regime officially collapses.

May 1, 2003 — President George W. Bush declares “mission accomplished” as the Pentagon says major combat is over in Afghanistan.

2004 and 2009 — In two general elections, Karzai is elected president for two consecutive terms.

Summer 2006: With the U.S. mired in Iraq, the Taliban resurgence gains momentum with escalating attacks. Soon they begin retaking territory in rural areas of the south.

April 5, 2014 — The election for Karzai’s successor is deeply flawed and both front-runners, Ashraf Ghani and Abdullah Abdullah, claim victory. The U.S. brokers a deal under which Ghani serves as president and Abdullah as chief executive, starting an era of divided government.

Dec. 8, 2014 — American and NATO troops formally end their combat mission, transitioning to a support and training role. President Barack Obama authorizes U.S. forces to carry out operations against Taliban and al-Qaida targets.

2015-2018 — The Taliban surge further, staging near-daily attacks targeting Afghan and U.S. forces and seizing nearly half the country. An Islamic State group affiliate emerges in the east.

September 2018 — After his election promises to bring U.S. troops home, President Donald Trump appoints veteran Afghan-American diplomat Zalmay Khalilzad as negotiator with the Taliban. Talks go through 2019, though the Taliban refuse to negotiate with the Kabul government and escalate attacks.

Sept. 28, 2019 — Another sharply divided presidential election is held. It is not until February 2020 that Ghani is declared the winner. Abdullah rejects the results and holds his own inauguration. After months, a deal is reached establishing Ghani as president and Abdullah as head of the peace negotiating committee.

August 18, 2019 — The Islamic State group carries out a suicide bombing at wedding in a mainly Hazara neighborhood of Kabul, killing more than 60 people.

Feb. 29, 2020 — The U.S. and the Taliban sign a deal in Doha, Qatar, setting a timetable for the withdrawal of the around 13,000 U.S. troops still in Afghanistan and committing the insurgents to halt attacks on Americans.

Sept. 12, 2020-February 2021 — After months of delay, Taliban-Afghan government negotiations open in Qatar, sputter for several sessions and finally stall with no progress. Ghani refuses proposals for a unity government, while the Taliban balk at a cease-fire with the government.

March 18, 2021 — After the U.S. proposes a draft peace plan, Moscow hosts a one-day peace conference between the rival Afghan sides. Attempts at a resumption of talks fail. Taliban and government negotiators have not sat at the table since.

April 14, 2021 — President Joe Biden says the remaining 2,500-3,500 U.S. troops in Afghanistan will be withdrawn by Sept. 11 to end America’s “forever war.”

2019-Present — Violence grows in Kabul. IS carries out brutal attacks, including on a maternity hospital and a school, killing newborns, mothers and schoolgirls. Also growing is a wave of random attacks, unclaimed and mysterious, with shootings, assassinations and sticky bombs planted on cars, spreading fear among Afghans.

May 2021-Present — Taliban gains on the ground accelerate. Multiple districts in the north, outside the Taliban heartland, fall to the insurgents, sometimes with hardly a fight. Ghani calls a public mobilization, arming local volunteers, a step that risks compounding the many factions.

July 2, 2021 — The United States hands over Bagram Airfield to Afghan military control after the last troops in the base leave. The transfer of Bagram, the heart of the U.S. military's presence in Afghanistan throughout the war, signals that the complete pullout of American troops is imminent, expected within days, far ahead of Biden's Sept. 11 timetable.