The hilly stretch of highway south of Kabul offers a picturesque view of Afghanistan's jagged mountains topped with silvery traces of ice. But the road could also spell trouble for the Afghan capital.
It's a dangerous smuggling route for weapons and bombs flowing into Kabul from southern Afghanistan and neighboring Pakistan. Curbing that flow is part of stepped-up efforts to tighten security in areas that serve as gateways into Kabul, where insurgents like to stage high-profile attacks.
"This is kind of a choke point," Lt. Col. William Chlebowski said, standing on the road in Logar province, which is next door to the capital. "The stuff comes from Pakistan through here."
There have been about six suicide attacks in the first half of this year inside Kabul's city center, down from 13 recorded by the U.N. during the same period in 2010. The reduction has been attributed to increased security inside Kabul and on roads leading into the capital. By comparison, many parts of Afghanistan _ especially in the south and east _ are subject to near daily attacks.
Security, however, remains tentative, aid groups and other western workers are often under travel restrictions in the city and one large-scale attack can change feelings about how safe Kabul is today.
Chlebowski observed an Afghan security force checkpoint being built here, then scaled a steep hill nearby to inspect the construction of two observation posts. From the lookouts, Afghan forces will be able to monitor foot and vehicle traffic moving through the mountains and valleys below.
"The key is establishing the presence here of the Afghan security forces," said Chlebowski, commander of the 5th Battalion, 25th Field Artillery Regiment.
Attacks in Kabul won't be stopped 100 percent, he said. More important is that the people think the capital is safe, he said.
Few would argue that Kabul is safe, though insurgent violence inside the city so far this year has been less deadly than last, when some Afghan parents refused to let their children go to school.
"The biggest challenge here are suicide bombers," said Noorullah, a police commander at a crowded, noisy checkpoint in central Kabul where military convoys shared the road with ice cream vendors, cars, trucks and donkey carts.
"Most of the time, the insurgents come in from the south or east," said Noorullah, who uses only one name. "Sometimes they are using cars that are not suspicious, like ambulances."
In the most recent attack, a suicide bomber wore an Afghan police uniform to gain access last month to the main Afghan military hospital in Kabul. He killed six medical students. A month before that, a suicide attacker in an army uniform sneaked past security at the Afghan Defense Ministry, killing three.
Earlier this year, suicide bombers attacked a Western-style shopping mall, killing two security guards, and a Western-style supermarket, killing eight Afghans. The first suicide attack in the city this year was carried out by a bomber on a motorbike. He targeted a minibus carrying Afghan intelligence employees, killing at least two and wounding more than 30.
The work to foil attacks on Kabul starts far from the capital.
The checkpoint Chlebowski visited is in Khoshi district in the remote mountains of Logar, more than 37 miles (60 kilometers) away. It is about 15 miles (25 kilometers) east of Pul-e-Alam, the capital of Logar. Once in Pul-e-Alam, insurgents can turn onto Highway 7 and head straight north into Kabul.
Another route to Kabul from the south is along Highway 1 in Wardak province next to Logar. There's also a highway that runs east out of Kabul into Nangarhar province and on to the Pakistan border.
On his way to the checkpoint under construction, the colonel passed members of the Kuchi nomadic tribe. They are suspected of smuggling weapons and explosives for the Taliban.
"They are absolutely bringing stuff in _ that's common knowledge," Chlebowski said. "To be truthful, I thought that maybe we should have stopped and searched them. There were a lot of them."
In March, an Afghan civilian told Afghan security forces that a tractor trailer filled with bomb-making materials would be passing through Sayd Abad district in Wardak. Afghan police stopped the vehicle and found 10 suicide vests, 17 spools of detonation cord, 30 cell phones and more than 600 pounds (272 kilograms) of explosive chemicals. The driver got away.
Haqnawaz Haqyar Wardak, provincial police chief of Wardak province, says insurgents continue to launch attacks in the province but are not a strong fighting force.
"They are like a thief in the night _ coming quickly, planting a mine or ambushing and then running away," he said. "Security this year has improved. There are difficulties. We cannot say there aren't. But there is no front."
Shajahudin Shejah, deputy governor of Logar province, said that last year, militants ambushed troops and travelers on Highway 1 and set up fake checkpoints where they stopped vehicles to shake down the occupants. A few weeks ago, insurgents learned that an Afghan policeman was going to be driving into Logar province in a station wagon. They stopped the vehicle, kidnapped the officer and killed him, Shejah said.
"But that is the only such incident since January," he said. "Last year, there were many incidents like this." Shejah did not provide details or elaborate further.
Insurgents might be moving through Logar to conduct attacks in the capital, but the deputy governor said the militants who live there are not strong enough to orchestrate large attacks.
"It is possible for a suicide attacker to pass into Kabul from Logar, but it is not possible anymore for a big group of insurgents to move through the province," he said. "If anybody says that Logar is a threat to Kabul, that is untrue."
Sayed Ghafar Sayedzada, general chief director of fighting terrorism for the Ministry of Interior, said that while coalition and Afghan convoys still get ambushed on the highway, he has received intelligence reports indicating that the Taliban fear traveling the road even in groups of five or six.
"We have cleared many areas, but some insurgents are still planning and organizing their attacks from the other side of the border in Pakistan and then using the road," he said. "It is not easy to block all the ways in."
Sayedzada said he's especially concerned about two areas near restive Surobi district in the far eastern part of Kabul province. The areas are heavily influenced by militants and need to be the focus of large-scale Afghan and coalition operations.
"We need to strengthen our intelligence not only in Kabul, but in the neighboring provinces too," he said. "Unfortunately, we have weak security in Nangarhar and we have to work harder in Wardak and Logar provinces and push harder on the enemy to prevent them from entering Kabul."