FARKHAR DISTRICT, AFGHANISTAN -- Mohammed Sohrab, a tall man, clad in Soviet Army combat fatigues with an assault rifle slung across his back, watched the attack unfold with a critical eye.

A group of guerrillas scattered across the open ground advanced methodically on their target. One man, covered by fire from his flanks, sprinted forward to fling himself behind the shelter of a rock and squeeze off a long burst of automatic fire at the slopes ahead. As he fired, another man was up and moving, dodging and weaving toward the next cover.

Once close enough, the 10 mujaheddin resistance fighters rose in unison for the final rush, the valley echoing with the storm of rifle fire and the whine of bullets ricocheting off rock. Then, as they halted, a sudden silence fell.

"Still too slow on your feet," bellowed Sohrab in Dari, the dialect of Persian spoken in northern Afghanistan. "And still not enough fire control. But better than yesterday."

Under the aegis of a growing regional command here in Afghanistan's northeast, Sohrab and other instructors are forging a new type of guerrilla force for their 8-year-old fight against the Soviet and Afghan government armies.

Reflecting the society they come from, most of Afghanistan's mujaheddin, or Moslem holy warriors, have little training, are often illiterate, and fight in insular groups whose members come from the same village or mountain valley.

But in this and similar camps, commanders of the Jamiat-i-Islami, one of Afghanistan's seven main resistance groups, are creating new fighting units of 25 to 30 fighters each. Drawn from throughout northeastern Afghanistan and trained together to build group unity and discipline, these "central units," as they are called, are designed as the nuclei of an eventual Afghan liberation army.

In this remote training camp in the mountains of northern Takhar Province, infantry tactics and the intricacies of "fire and movement" are one subject drilled by Sohrab. A specialist in mortars and recoilless rifles -- and a veteran of years of fighting in his native Panjsher Valley -- Sohrab prefers to give instruction in heavy weapons. Colleagues, many also Panjsheris, teach courses in mines and mine-clearing, booby traps, surface-to-surface rockets and other lethal staples of Afghanistan's guerrilla war.

Concealed in a narrow valley and overshadowed by nearly sheer rock walls, the training facilities here are rudimentary. The camp includes newly built barracks, a kitchen, a mosque doubling as lecture hall, storerooms, arms dumps, a firing range and a sports field.

Despite its simplicity, the Takhar camp and others like it in neighboring provinces reflect a new phase in the evolution of the Afghan war. They also underscore the growing maturity and independence of a centralized resistance command in the northeast headed by guerrilla strategist Ahmed Shah Massoud.

Set up last year, the camps and the units they train come under the command of Jamiat-i-Islami's Supervisory Council of the North, which, under Massoud, coordinates the resistance party's units in several northeastern provinces, dominated by ethnic Tajiks and Uzbeks.

Afghan and foreign observers of the war agreed that the "central units" mark basic innovations in the resistance's military organization. Analysts noted that the geographically mixed composition of each group counters the chronic localism that has plagued the Afghan resistance and underlain much of the infighting in its ethnically and linguistically diverse ranks.

"There are men in this group from Takhar, Panjsher, Andarab, Khost, Parwan and Kabul," said Sohrab after the live-ammunition "fire and movement" exercise. He was referring to provinces and major valleys on both the southern and northern flanks of the Hindu Kush range that stretches across northeastern Afghanistan.

"In the coming months we hope to get men from Kunduz also," he added. Kunduz is a northern border province west of Takhar.

The central units also display a military professionalism that foreign observers have found lacking among the undisciplined and ill-organized bands of fighters typical of the vast mass of the Afghan resistance.

The most visible sign of this new professionalism is a basic uniform of Soviet Army combat fatigues, boots and belts -- bought on a flourishing black market in surplus Soviet military goods -- and the flat woolen caps favored by the mujaheddin of eastern Afghanistan. Still, it is discipline, better weaponry, higher educational standards and ideological training in Islamic studies that have been most important in building an esprit de corps among men now widely viewed in the northeast as an elite force.

Central units have been divided into two categories -- infantry formations, and those armed with heavier weapons such as mortars, heavy machine guns, recoilless rifles and ground-to-ground rockets. And, according to Massoud, central forces teams specializing in antiaircraft weapons, including U.S.-supplied Stinger missiles, will soon be formed. The mujaheddin of the Supervisory Council of the North already field Stingers.

Other specialized teams already attached to Massoud's mobile headquarters include cartographers, demolition and explosives experts, and radio communications specialists.

First formed in early 1985, the central forces were built around a core of experienced mujaheddin from the Panjsher Valley, veterans of bitter fighting in the early years of the war. Believed now to number several hundred men, the units have been in operations across the northeast, notably the capture of a string of government garrisons in the past two years.

But Massoud stressed that, while these groups are deployed as combat units, they are intended primarily to offer training and experience for a cadre of leaders who will provide the backbone of a future national army.

"We have begun the first stages in the creation of a real army of resistance," Massoud said in an interview in September. "The aim of the central units is the training of future cadres for that army."

The new-style central forces now form the apex of a pyramid of military organization developed in the Panjsher between December 1979, when the Soviet Union invaded Afghanistan to prop up a crumbling communist regime, and 1985, when Massoud left the valley to extend organizational work to the north. Since then the Panjsher model has, to greater or lesser extent, been adopted by allied commanders across the northeast.

At the base are formations known as "security groups." Consisting of lightly armed local men, they fulfill a mainly internal security role in zones controlled by the resistance.

Local defense is undertaken by "strike groups," usually 30 to 50 strong, they are intended to fight primarily within their immediate area.

Above them are better armed "mobile groups," with light support weapons -- rocket-propelled grenades, machine guns and light mortars. These groups are intended to operate within a guerrilla base area, which in the northeast usually takes the form of a large valley.

Resistance sources noted, however, that in practice the deployment of units has been flexible and both mobile and strike units are moved as operations require. At the capture of the Afghan Army garrison of Koran in Badakhshan Province in late October, mobile units from the Panjsher Valley and from Nahrin in Baghlan Province were used, as well as strike units from the Khost and Ursaj regions of Takhar Province.

At the pyramid's apex are the central forces, taking orders from Massoud's central headquarters and available for deployment across the northeast or even beyond.

At the Takhar camp, basic training for guerrillas -- all of whom have had fighting experience -- takes one month. But, with a view to combining theory and practice, a unit being formed will shift from a training camp to a real operation and then back to the camp, instructors said.

The long winter months, when fighting in Afghanistan usually slackens, are generally favored for instruction, they added. The camps also are used for mujaheddin from other regions requiring far more basic training than that given central units.

During a western reporter's week-long stay at the Takhar camp, Jamiat-i-Islami fighters from northern Jowzjan Province and from the Kabul area were also being put through courses. Instructors noted that, in the interests of forging a wide resistance front, courses had also been given to mujaheddin from parties other than Jamiat.

The camp routine, starting at 4 a.m., was taxing. But the gruelling physical and psychological stresses associated with the training of western elite forces were notably absent.

The morning was devoted to military and physical training, which in the first month includes tactics, map reading and proficiency courses in heavy weapons.

But almost equal emphasis was laid on Islamic studies and "ideological training." In addition to the five daily prayers expected of practicing Moslems, the camp routine included an hour's study of the Koran after dawn. In the afternoon, three hours were devoted to lectures on Islamic theology and history as well as classes covering recent Afghan history and international affairs.

Literacy classes were also provided for men without basic schooling -- a small minority in central units, for which literacy is generally a prerequisite.

From what a western reporter with a fair knowledge of Persian was able to observe over a week, the political-religious training was notably devoid of the strident sloganeering and indoctrination associated with Iran's Revolutionary Guards.

"We're not fanatics," said Ghulam Haider, an 18-year-old from the Khost region of Takhar. "What I have learned here is a far better understanding of the Koran."

Senior resistance officials said the ideological courses were necessary to impart a commitment to the resistance cause and guard against poor discipline, particularly towards civilians.

"Jihad {holy war} is based on a belief that for Moslems it is a religious duty to defend religion, honor and country," said Mohammed Es'Haq, a senior Peshawar-based Jamiat official, recently in the northeast.

"But that is a very general idea," he added. "In order to give fighters a thorough understanding of their mission we have to explain what mujaheddin should really be and how they should behave. There is a need to educate them and explain how the prophet Mohammed and his followers launched jihad. We have to follow that model."

Discipline among central units had a distinctly Afghan flavor, which by western standards would be considered lax. Unit commanders, not distinguishable by any insignia, mixed easily with their men, eating with them and sharing the same basic barrack accommodation.

Still, unlike many resistance groups, where traditionally proud Afghans practice a free-wheeling military democracy, the men of Massoud's central forces did not question orders. The taking of snuff and cigarette smoking, both popular among Afghan men, were strictly prohibited in central units on health and financial grounds.

The establishment of training camps and the emergence of the central forces have helped underscore the growing self-reliance and independence of Massoud's Supervisory Council of the North. As one commander put it: "All the military and political training we need can be done right here."

In an interview, Massoud described his relations with Jamiat's Peshawar headquarters as close and noted that all decisions made in the northeast were approved by Jamiat leader, Burhanuddin Rabbani. A religious scholar, Rabbani is widely respected in his home province of Badakhshan and the northeast in general.

According to informed sources, Massoud has sought not to be perceived as attempting to usurp a position of political leadership despite his considerable military successes. In schools and other public buildings in areas controlled by the Supervisory Council, pictures of Rabbani rather than the popular Massoud adorn the walls.

Nevertheless, sources noted that Massoud's growing stature has irritated some within the Pakistani military. The conduit for the resistance's arms from foreign sources, the Pakistani military is understood to prefer maintaining relations with major commanders from the Afghan interior. But the Pakistanis have had little or no contact with Massoud.

Observers noted that most leading mujaheddin commanders had visited Peshawar at least once in recent years. But since he left for the Panjsher Valley to lead the resistance there in 1979, Massoud has never returned to Pakistan.