By Robin Emmott and Sabine Siebold

BRUSSELS/BERLIN (Reuters) – Foreign troops under NATO command will withdraw from Afghanistan in coordination with a U.S. pull-out by Sept. 11, NATO allies agreed on Wednesday, pledging to mirror American plans to start removing troops on May 1 after two decades of war.

Around 7,000 non-U.S. forces from mainly NATO countries, also from Australia, New Zealand and Georgia, outnumber the 2,500 U.S. troops in Afghanistan, but still rely on American air support, planning and leadership for their training mission.

NATO Secretary-General Jens Stoltenberg, speaking alongside U.S. Secretary of State Antony Blinken and U.S. Defense Secretary Lloyd Austin, said the decision was tough.

“This is not an easy decision, and it entails risks. As I said for many months, we face a dilemma. Because the alternative to leaving in an orderly fashion is to be prepared for a long-term, open-ended military commitment with potentially more NATO troops,” Stoltenberg told a news conference.

Biden gave a speech on Wednesday in Washington announcing the U.S. withdrawal, saying that “it’s time to end the forever war.”

An integral part of NATO’s current mission, Resolute Support, is to train and equip Afghan security forces fighting the Islamist Taliban, which was ousted from power by a U.S. invasion in 2001 and has since waged an insurgency.

With non-U.S. troop numbers reaching as high as 40,000 in 2008, Europe, Canada and Australia have moved in tandem with the United States in a mission also providing long-term funding to rebuild Afghanistan despite the resurgence of Taliban-led violence and endemic official corruption in the country.

“This is not the end of our relationship with Afghanistan but rather the start of a new chapter. NATO allies will continue to stand with the Afghan people but it is now for the Afghan people to build a sustainable peace that puts an end to violence,” Stoltenberg said.

Germany and Bulgaria were two of the 36 countries involved in Resolute Support to immediate announce withdrawal plans. German Chancellor Angela Merkel and Biden discussed in a phone call the NATO military presence in Afghanistan and agreed to closely coordinate future steps, a German government spokesman said.

Sept. 11 is a highly symbolic date as it will be 20 years since al Qaeda attacked the United States with hijacked airliners, triggering military intervention in Afghanistan.

After withdrawing, the United States and NATO aim to rely on Afghan military and police forces, which they have developed with billions of dollars in funding, to maintain security, though peace talks are struggling and the insurgency is resilient.

A key reason for a coordinated withdrawal is the fact that NATO relies on U.S. airlift capabilities and shipping to move valuable equipment back home out of landlocked Afghanistan. NATO also wants to avoid any hardware falling into the hands of militants, as happened after the U.S. withdrawal from Iraq.

(Reporting by Robin Emmott; Editing by Mark Heinrich and Will Dunham)