KABUL - U.S. General David Petraeus, Washington's new intelligence chief, handed over command of U.S. and NATO-led troops in Afghanistan on Monday, a day after a tentative start was made to a gradual process of transferring security to Afghan forces.
Petraeus, credited with reversing a spiral towards civil war in Iraq, took over in Afghanistan on July 4, 2010, and is leaving the military to take over as director of the Central Intelligence Agency as part of a wider shake-up of senior U.S. security officials.
Petraeus oversaw a "surge" of 30,000 extra U.S. forces which helped stop the momentum of a growing insurgency, especially in the Taliban heartland in the south.
However, despite gains in violent southern provinces during Petraeus' year in charge, the Taliban-led insurgency is still far from quelled.
Violence across Afghanistan in 2010 hit its worst levels since the Taliban were ousted by U.S-led Afghan forces in 2001, with civilian and military casualties hitting record levels, and this year has followed a similar trend.
"We should be clear-eyed about the challenges that lie ahead," Petraeus said at a ceremony to mark the change of command of the NATO-led International Security Assistance Force (ISAF) to U.S. Marine Corps General John Allen.
Underlining those challenges, ISAF said on Monday three of its troops had been killed by a homemade bomb in Afghanistan's east, where some of the toughest fighting has taken place over the past year and where a fractured insurgency still rages.
While some analysts have questioned the success of Petraeus' much-vaunted counter-insurgency strategy in the face of rising violence, Allen vowed to press on but also warned of the challenges ahead.
"It is my intention to maintain the momentum of this great campaign on which we have embarked," Allen said. "There will be tough days ahead."
On Sunday, ISAF handed security control over to Afghan forces in central Bamiyan province, marking the start of a gradual transition process that will end with all foreign combat troops leaving Afghanistan by the end of 2014.
Bamiyan was the first of seven areas to be handed over during the first phase of transition. Another district in eastern Laghman province will be handed over to Afghan forces on Tuesday.
Lashkar Gah, the capital of volatile Helmand province and the most contentious of the first seven areas, will be handed over on Wednesday.
"Our military presence will diminish, as it should, after 2014 but the partnership between our two nations will and must continue," Admiral Mike Mullen, the chairman of the U.S. Military's Joint Chiefs of Staff, told the ceremony at ISAF headquarters in Kabul.
While foreign troops under Petraeus' command made significant gains over the past year, the Taliban and other insurgents have still been able to launch attacks in major centres and the number of targeted killings of Afghan officials has grown significantly.
Late on Sunday, gunmen killed an adviser to Afghan President Hamid Karzai and another Afghan lawmaker, days after Karzai's half-brother was assassinated in Kandahar province, the birthplace of the Taliban.
Those killings have sent chilling warnings to political leaders about the reach of the Taliban, who have shown an ability to adapt their tactics even as their strength has been diminished.
Petraeus is expected to begin his new job at the CIA in September. (Editing by Yoko Nishikawa)
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