The head of NATO, Secretary-General Jens Stoltenberg, confirmed Thursday that the coalition would begin withdrawing from Afghanistan on May 1, the original deadline set in a deal brokered by the administration of President Donald Trump, but extended this week under successor Joe Biden.

Biden announced Wednesday that American troops would leave Afghanistan by September 11, the 20th anniversary of the al-Qaeda attacks on New York and Washington, D.C. Cooperation between the Afghan Taliban and al-Qaeda led President George W. Bush to invade Afghanistan in the quest to find terrorist leader Osama bin Laden in October 2001.

Biden has branded his extension of the 19-year-old war to its 20th birthday a political statement that the war had gone on too long.

“I’ve concluded that it’s time to end America’s longest war,” Biden said in his announcement prolonging the war.

Trump administration Secretary of State Mike Pompeo brokered a deal with the Taliban late last year that required the group to stop cooperating with foreign terrorist organizations and stop attacking American soldiers in exchange for the United States withdrawing from the country by May 1, 2021. Both sides accused the other of violating the deal — the Taliban complaining that the American military did not appear to be planning a departure and the U.S. government claiming the Taliban maintained ties to al-Qaeda — and Biden did not clarify he would violate the deal until Wednesday.

In remarks at a joint press conference with Biden’s Secretary of State Antony Blinken, currently in Kabul, and Defense Secretary Lloyd Austin, Stoltenberg said NATO would begin to withdraw in May, not September. Under Article 5 of the North Atlantic Treaty, an attack on any NATO country is considered an attack on them all. Bush invoked Article 5 to attack Afghanistan collectively with NATO following the September 11 attacks.

“We went into Afghanistan together; we have adjusted our posture together, and we are united in leaving together,” Stoltenberg said, according to Afghanistan’s Tolo News. He noted that the alliance has about 10,000 troops in the country.

“Standing shoulder to shoulder, we have paid a high price, in both blood and in treasure. Thousands of our troops from Allied and many partner nations, and from Afghanistan, have paid the ultimate price. Many more have been wounded,” Stoltenberg contined. “We have also helped to build the Afghan security forces from scratch. With great bravery and professionalism, they have provided security across their country over the last years.”

Some allies have already left the country. In February, the government of New Zealand announced a full withdrawal of its six troops regardless of Washington’s desire to meet its May 1 deadline. New Zealand is not a member of NATO but cooperated with the alliance in the country.

At the same press conference, Blinken justified keeping American troops in the country an extra four months by insisting the original mission of the invasion, to capture or kill Osama bin Laden, had long been met.

“We don’t believe that maintaining an indefinite troop presence in Afghanistan, is in our interests, not for the United States, not for NATO and our Allies,” Blinken said, without elaborating on what the U.S. hoped to accomplish between May and September 2021.

Blinken promised that the U.S. will “keep investing in the well being the Afghan people” beyond September.

The official government of Afghanistan, which has seen heightened Taliban attacks on its forces in recent months as the jihadists shifted focus away from U.S. troops, expressed concern this weekend that a withdrawal of U.S. troops soon may be too hasty.

“If the Taliban feels that there will be chaos here and they will achieve power, this is their miscalculations because no one supports the return of the Taliban,” National Security Adviser Hamdullah Mohib said this weekend.

Kabul is attempting negotiations with the Taliban hosted by Turkey. Direct negotiations between the two have been marred for decades by the fact that the Taliban considers itself the only legitimate government of Afghanistan, refers to itself formally as the “Islamic Emirate of Afghanistan,” and considers the Kabul government a usurping puppet regime of the United States.

U.S. special envoy Zalmay Khalilzad, who has spearheaded the diplomatic wing of resolving the Afghan conflict under both Biden and Trump, has traveled to Turkey to participate in the talks, a sign that American involvement will continue heavily beyond an end to the military presence, if it occurs.

The Taliban have stated they will not participate in the Turkey talks, noting a deal is currently in effect between the U.S. and the Taliban — the deal that would have seen American troops depart on May 1.

“We can’t take part in Turkey’s conference on 16 April as discussions on attending the conference are under way,” Taliban spokesman Mohammed Naeem said this week.

The Taliban also responded sourly to Biden’s statement announcing a September withdrawal deadline, which appeared to disregard the deal implemented after talks with Pompeo.

“The Islamic Emirate will under no circumstance ever relent on complete independence and establishment of a pure Islamic system and remains committed to finding a peaceful solution to the Afghan problem following the complete and certain end of occupation,” the jihadist organization said in a statement, adding that violating the deadline “in principle opens the way for the Mujahideen of Islamic Emirate to take every necessary countermeasure, hence the American side will be held responsible for all future consequences, and not the Islamic Emirate.”

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