A giant US military base emerges in Afghanistan

In the forbidding Afghan desert, US engineers are carving out a sprawling military camp as part of a dramatic American troop build-up designed to confront Taliban insurgents.

The desolate plain in southern Helmand province that Afghans call the "desert of death" has turned into a hive of frenetic activity, underscoring President Barack Obama's decision to expand the US military commitment to the war.

Defence Secretary Robert Gates flew into Camp Leatherneck on Thursday to get a first-hand look as dozens of bulldozers kicked up clouds of dust and soldiers swung hammers in searing heat.

Some of the newly arrived soldiers at the camp told Gates they were still waiting for radios and other equipment to arrive.

Gates promised to look into the problem and said later at a news conference in Kabul that moving such a large number of troops and so much equipment was a "logistical challenge" in a country with a shortage of airports and major roads.

Every day military planes ferry in more marines and soldiers to the camp that has emerged out of the desert seemingly overnight, protected by miles of sand walls topped with barbed wire along with rows of barrier walls.

"It's been real busy," said Captain Jeff Boroway from the 25th Naval Construction regiment.

"This place was desert at the end of January. I mean nothing. And now you've got a 443-acre (179-hectare) secure facility," he told reporters.

Boroway said engineering units were rushing to finish work on the camp to accommodate the deployment of thousands of additional troops, including most of an 8,000-strong brigade of US Marines.

The escalation of the war against the Taliban has raised concerns among some in Obama's own party that the administration could be drawn into an open-ended mission.

But US commanders and officials say their aim is to train Afghan forces to eventually take over security duties.

The camp, which is being built next to a smaller outpost dubbed "Bastion" that has served British troops, will include a vast airfield that eventually will be home to 55 helicopters and other aircraft, said Lieutenant Colonel David Jones.

The airfield, which he called a huge "parking space" for choppers, will be 4,860 feet (1,481 metres) long and is the largest such project in the world in a combat setting, said Jones, who leads a marine squadron in charge of the effort.

The labour-intensive work requires levelling off the runway area and setting down sheets of metal alloy that are then anchored into a mat.

The runway project began about a month ago and has to be finished by the end of June, officers said.

The temporary metal mat, which will later be replaced with asphalt, "provides a secure place for any aircraft to land, park and take off," Boroway said, and is "a lot safer and better than dirt."

He said his troops and contractors have moved mountains of sand in their efforts to boost defences.

They are also expanding another US base in the southern city of Kandahar.

All the digging and bulldozing in the desert has put a premium on water, especially for the runway construction.

As a result, troops were collecting water from the base's kitchens and showers to compact dirt at building sites, the Navy officer said.

The base is needed quickly with the US military presence in Afghanistan due to double by the autumn, when the Obama administration says up to 68,000 troops will be in place.

Boroway said his team was working 12-hour days in searing heat to finish. "They know the importance of this," he added.