KABUL, July 18 (Reuters) - U.S. General David Petraeus, Washington's new intelligence chief, handed over command of foreign troops in Afghanistan on Monday but worsening violence cast a shadow over the tentative start of a process to transfer security to Afghan forces.
Eleven Afghan police were killed on Monday, seven of them in an attack by Taliban gunmen on a police checkpoint in the volatile southern city of Lashkar Gah which is to be handed over to Afghan security forces in two days.
The frequency and scale of recent attacks have been a worrying sign as the transition process begins, with U.S. and other NATO forces racing to train enough soldiers and police to take over completely and allow all foreign combat troops to leave Afghanistan by the end of 2014.
Daoud Ahmadi, a spokesman for the governor of Helmand province, where much of the fight against the Taliban had been focused during Petraeus' tenure, confirmed the attack and said seven police were killed.
The Taliban quickly claimed responsibility.
In neighbouring Kandahar province, the birthplace of the Taliban, a district police chief and another three officers were killed by a roadside bomb, one of the most lethal weapons employed by insurgents.
"The Afghan people and the government are committed in implementing the transition process despite all the disruptions created," Waheed Omer, the chief spokesman for Afghan President Hamid Karzai, said of the recent spike in violence.
"Efforts have been intensified to disrupt this process, efforts have been made to disable the Afghan government and people from taking responsibility for security," he said.
CIA DIRECTOR
Petraeus, credited with reversing a spiral towards civil war in Iraq, took over in Afghanistan a year ago. He is leaving the military to take over as director of the Central Intelligence Agency, replacing Leon Panetta, the new U.S. defence secretary.
Petraeus, who handed over to U.S. Marine Corps General John Allen, 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. He led a similar escalation of forces that helped turn around the Iraq conflict in 2007-08.
However, despite gains in violent southern provinces during Petraeus' year in charge, recent attacks have shown 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.
In another especially gruesome incident on Monday, two Afghans were beheaded in the west, villagers and police said. They were kidnapped along with 33 others last week for apparently supporting the Afghan government.
Their beheaded bodies were sent back to their families.
CHALLENGES AHEAD
Petraeus and other senior officials at the change-of-command ceremony acknowledged that more tough fighting remained despite gains that have been made over the past year.
"We should be clear-eyed about the challenges that lie ahead," Petraeus, who is expected to take over at the CIA in September, said at the NATO-led International Security Assistance Force (ISAF) headquarters in Kabul.
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.
Some analysts have questioned the success of Petraeus' much-vaunted counter-insurgency strategy in the face of rising violence. But Allen vowed to press ahead.
"It is my intention to maintain the momentum of this great campaign on which we have embarked," Allen said.
On Sunday, ISAF handed security control over to Afghan forces in central Bamiyan province, marking the formal start of the gradual transition process.
Bamiyan, one of the safest of Afghanistan's 34 provinces and long an anti-Taliban redoubt, was the first of seven areas to be handed over during the first phase of transition.
Lashkar Gah is one of the next to be handed over. U.S., British and Afghan troops swept through the sparsely populated desert outside the city at the weekend to root out Taliban fighters who might try to disrupt the transfer.
"This is very important for our security. It's also important for the transition of Lashkar Gah. We will make a screen for the Taliban not to cross or bother our security build-up," Afghan Army Major Mohaib told Reuters.
The first phase of transfers, mostly in areas considered relatively safe, will be a critical test of the readiness of Afghan forces.
Late on Sunday, gunmen killed an adviser to Afghan President Hamid Karzai and another Afghan lawmaker, days after Ahmed Wali Karzai, the president's half-brother and one of the most powerful men in Kandahar, was killed.
Last month, Taliban gunmen and suicide bombers attacked a leading hotel in the capital in a raid which killed 12 people.
Such killings, many claimed by the Taliban, 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.