After almost two weeks, Donald Rumsfeld's laconic briefings at the Pentagon have acquired a familiar feel.

But how is this American-led war on terrorism going? Is the military campaign changing and what is likely to happen next?

A breakdown of Operation Enduring Freedom so far:

Targets

Much of the bombing to date has been against so-called "fixed" targets.

These include barracks, training camps, airfields and air defences.

Numerous other moveable targets have also been hit, including aircraft, tanks and other vehicles.

Much of the Taleban's heavy equipment is thought to be of doubtful serviceability, but the Pentagon has clearly worked on the assumption that some aircraft and missiles might work and targeted as much as it can find.

This allowed Donald Rumsfeld to announce, early on, that US jets had command of the skies.

In some areas, the original target lists have been all but exhausted.

In recent days, American strike aircraft have operated in what are known as "engagement zones", where certain types of target are known to exist and where airborne controllers identify and direct the attacks.

It is a strategy which could continue almost indefinitely.

One of the aircraft used in such operations is the fearsome AC-130, a gunship capable of devastating assaults on troop formations and concentrations of vehicles.

Ground troops

The second phase of the operation in Afghanistan appears to have begun, with the announcement by US officials that more than 100 elite forces carried out a secretive ground assault in southern Afghanistan in the early hours of Saturday morning, local time.

They said the operation, backed by AC-130 flying gunships, lasted several hours but would give no other details.

Earlier they confirmed that special forces are now operating inside Afghanistan.

They appear to fall into two categories: a small team of soldiers, possibly accompanied by CIA officers, working among Pashtun tribesmen to whittle away at the Taleban's power base; another offering help to the anti-Taleban Northern Alliance in areas such as intelligence and reconnaissance.

Aid and propaganda

Criticised as tokenism by some humanitarian organisations, America's nightly air drops continue.

By Friday, the official total was in excess of half a million packets (each packet containing rations for one adult for one day).

Washington has been getting its message across in two ways.

EC-130 "Commando Solo" psychological operations planes have been broadcasting a variety of messages, including support for the people of Afghanistan and warnings not to interfere with ground troops, and to stay off roads and bridges.

"Attention! People of Afghanistan. United States forces will be moving through your area," one broadcast message says.

"Do not interfere with our troops or military operations. If you do this, you will not be harmed."

Leaflets with similar messages are also being dropped.

The net result

The Taleban have taken a pounding, though little battle damage assessment has been released and observers on the ground point out that in this impoverished country, military hardware counts for less than basic loyalty.

Reports of Taleban defections have been sporadic and largely unconfirmed.

But coalition bombing must have significantly disrupted the Taleban's ability to function.

Pentagon officials say communications have been completely severed.

Taleban commanders in one area may know little about events elsewhere in the country.

Fighting blind, the Taleban may find it hard to hold on much longer.

The way ahead

Raids such as the special operation on Saturday morning could be a major element of the war from now on. The aim would be to turn the tables on the Taleban by using their own guerrilla tactics against them

This new phase is what the British Prime Minister, Tony Blair, seemed to have been hinting at earlier this week when he warned that "the next few weeks will be the most testing time".

But with political sensitivities high and winter approaching, a substantial land incursion is thought to be unlikely, although one senior British defence source said more visible ground operations could begin "within weeks".

"Sooner or later, the present government will fold or sue for peace," he said, "and then we'll have to move fast."

"We definitely wouldn't leave a vacuum", he added, noting that ground troops would only be part of a wider package of international intervention, including aid and financial assistance.