The U.S. Marines were tense looking for bombs buried near a mud compound in this remote farming town in southern Afghanistan. Their new Afghan police colleagues were little help, joking around and sucking on lollipops meant for local kids.

The government had sent the new group of 13 police to live and train with the Marines just a few days earlier. Most were illiterate young farmers with no formal training who had been plucked off the streets only weeks before.

Building a capable police force is one of the keys to President Barack Obama's new Afghan strategy. U.S. Defense Secretary Robert Gates met with Afghan President Hamid Karzai in Kabul on Tuesday to discuss how to recruit more Afghan police to meet Washington's goal of expanding the force from about 94,000 today to 160,000 by 2013.

The Marines' experience in Khan Neshin, once a key Taliban stronghold in volatile Helmand province, shows just how difficult the task will be.

The provincial government fired the last group of police assigned to Khan Neshin after more than half of them failed a drug test, prompting them to rebel by throwing rocks at the Marines. When the police weren't smoking drugs, Afghans complained they were taking goods from the bazaar without paying.

"The guys who were here last time put a bad taste in people's mouths by being typical of what people think of the Afghan National Police," said Gunnery Sgt. Randy Scifo, a military policeman from the 1st Marine Division who recently took over responsibility for the police in Khan Neshin.

Scifo said he was surprised the new group showed up without any training, but the police academy on a coalition base near the provincial capital of Lashkar Gah was full. The Marines expect to receive more than 20 graduates from the school toward the end of the month and will send this new group to the academy in January. Until then, they are not allowed to carry weapons.

"I want to bring peace and security to my country," said Mohamed Ullah, an 18-year-old with a wispy black beard from Helmand's northern Kajaki district.

The Marines spend their days teaching the recruits the basics of patrolling, sweeping the ground for buried bombs and searching people and vehicles. They prepared for their mission by working with a group of Afghan-Americans in a mock town set up on their base at Camp Pendleton, Calif., Scifo said.

But that training didn't prepare the Marines for all the cultural challenges they now face in an area where they are relying on their local counterparts for guidance.