Afghan army troops on Wednesday formally assumed the lead responsibility for security in Lashkar Gah, capital of Afghanistan's Helmand province. (Hamish Burke/AP)

Hurtling through this southern provincial capital in the back of a military pickup, Afghan army Sgt. Abdul Latif took one hand off his machine gun and pointed to signs Tuesday that foreign troops were still fixtures in the sky and on the ground.

A beige armored vehicle passed Latif’s pickup. “British,” he said. An Apache helicopter appeared overhead. “Americans,” he said. “Still here.”

On Wednesday, in a red-carpet ceremony, those foreign troops turned over security control of Helmand province’s largest city to the Afghan National Security Forces, part of a scheduled transition of seven Afghan cities or provinces this month. By most measures, Lashkar Gah is the least stable of the seven, with insurgents still thriving on the city’s outskirts.

The transition here is seen as a crucial test of the overall capacity of Afghan forces — a chance to gauge the abilities of troops and police in a place with no shortage of security challenges.

But only half of central Lashkar Gah — just over a square mile — will actually take part in the transition. The area is an island of relative security and marked progress in a region that continues to face grave threats from insurgents. That small swath of land has been controlled by Afghan forces for more than a year, and the official transition will bring little change, even as officials call this the beginning of the end for NATO’s military engagement in the region.

Meanwhile, the operations that could dictate the city’s future are being conducted just beyond its periphery, where a bustling bazaar gives way to scrubby farmland. This week, Latif and his unit continued a push northeast of the city, encountering fire from Taliban fighters on nearly every patrol. When those fights intensify, they call on foreign troops: British armored vehicles and U.S. Apaches.

“This is the front lines for us,” said Col. Ataullah Zahir, Latif’s commander, leaning against a mud-baked hut seven miles from central Lashkar Gah, a firefight echoing in the distance. “This is where we’re proving ourselves.”

Like other top Afghan officials here, Zahir boasts of recent gains and his battalion’s growing independence, pointing to the men on foot patrol with him: three-dozen Afghans and not a single soldier from NATO’s International Security Assistance Force. The men follow dirt roads through a former Taliban stronghold, brushing past poppy fields on their way north.

Zahir has drawn a bold vertical line on a map in his office, marking a boundary about 10 miles east of the city. As dignitaries discussed the symbolism of the city’s official transition, he rallied his men around an unofficial, far more ambitious idea: “We need to take responsibility for everything west of this line,” he said.

That ambition has impressed the British soldiers — his battalion’s mentors — who share a base with his men in the Afghan desert.

“Over the last few months, these guys have really started delivering the goods,” said British Capt. Matt Williams.

But policing the streets of Lashkar Gah and assuming responsibility for vast expanses of farmland where the Taliban have deep roots are wildly different challenges, Zahir said. Achieving operational independence in the rural parts of Helmand could take years.

“If the government tells us to be ready for transition, we’ll do our best. But we would really like some more time,” he said. “We still need aircraft assistance and armored vehicles.”

Zahir’s qualms underscore a fundamental truth of the transition process, which demands both progress and compromise. In more peaceful parts of the country, such as central Bamian province and the Afghan capital, Kabul, thousands of square miles of land have been entrusted to Afghan forces. But in Helmand, home to fierce fighting for much of the past decade, the only viable transition was a modest one.

Still, officials expect the symbolic importance of the process to bolster a sense of self-determination among Afghans, who have become accustomed to the presence of foreign security forces over the past decade.

“It’s not just a milestone for Lashkar Gah and Helmand,” said Michael O’Neill, head of mission at the Provincial Reconstruction Team here. “It’s a catalyst for further change.”

In practice, that security hand­off means that in two of the city’s four precincts, foreign troops will assist Afghans only if they are called on to do so. In the area that will be handed over to local forces, no such call has been made for more than a year.

“I told the president several months ago that we were ready for transition in Lashkar Gah,” said Gulab Mangal, the governor of Helmand. “Terrorists are active in the area, but they can’t fight the [Afghan forces] face to face.”

Officials in the central government were eager to include a city in the country’s volatile southern region on the list of transition locations, a decision that some questioned in the grim days leading up to the transition ceremony.

On Monday, an Afghan police officer poisoned and killed seven of his colleagues just east of the city. On Tuesday, a makeshift bomb was triggered near an ISAF base here. And on Wednesday, a bomb exploded near a police station on the city’s periphery.

With the official transition ceremonies over, Mangal has begun talks with central government officials about the next districts in Helmand that might take part in the transition.

But the more daunting timeline, Zahir said, is the one set by NATO, mandating that troops leave by 2014.

“We won’t know if we’re ready until the date arrives,” he said. “We can just hope.”