(CNN) -- The Netherlands became the first NATO ally to pull combat troops out of Afghanistan on Sunday, as it handed over its mission in southern Afghanistan's Uruzgan province to U.S. and Australian forces.
At the peak of their commitment, the Dutch had nearly 2,000 troops in Afghanistan. Some staff units remain in Afghanistan, according to the NATO-led International Security Assistance Force, but the Dutch government said the last of its troops will return by December.
"The past four years brought the population of Uruzgan great improvements," the Defense Ministry said in a statement Sunday. "Regrettably, the Netherlands is saddened by its 24 war casualties and 140 wounded."
The Dutch government already had extended its mission by two years. NATO requested another extension as the United States and its allies beefed up forces at the end of 2009, but opposition to the proposal brought down Dutch Prime Minister Jan Peter Balkenende's ruling coalition in February.
U.S. and NATO forces invaded Afghanistan in 2001 in retaliation for the al Qaeda attacks on New York and Washington that September. Allied and local forces quickly toppled the Taliban, the Islamic militia that ruled most of Afghanistan and allowed al Qaeda to operate within its territory.
But top Taliban and al Qaeda leaders escaped the invasion, and Taliban fighters regrouped along the rugged border between Afghanistan and Pakistan. The group is now battling both coalition forces in Afghanistan and Pakistan's government.
CNN's Ben Brumfield contributed to this report.