Afghan guerrillas have pulled back from their effort to capture the important garrison town of Jalalabad and the war in Afghanistan has settled once again into the uneasy rhythm of attrition.

Bands of Moslem fundamentalist rebels are now striking sporadically at military convoys and patrols. Some small garrisons are reported to have been cut off and are being resupplied by helicopter.

Intelligence sources report that the situation in the eastern border region of Paktia is still critical for the revolutionary government of Nur Mohammed Taraki, and rebel groups claim to have surrounded the town of Kunar, although no major actions so far have been reported there.

The biggest battles - involving the fight earlier this year for Afghanistan's second city in the west, Herat, and the recent thrust to take Jalalabad and cut main road to the Khyber Pass border crossing - are over for the time being. They have been costly to both sides.

Sources say that at the start of the attack to take Jalalabad last month about 10,000 armed rebels left the Peshawar region in Pakistan and crossed the border. The Pakistan government has consistently denied any involvement with the Afghan rebel forces.

The rebels are understood to have launched their action with insufficient ammunition, however, and were also slowed by some big and early losses that included a number of their commanders. Later, they ran short of food.

No casualty estimates are available, beyond the understanding that they were very high. Afghan security forces, faced with an assault of this sort, tend to react with massive force.

Near Jalalabad, Afghan planes bombed guerrilla position with napalm and launched rocket strikes. The rebels reportedly got no nearer than five miles northeast of the town before abandoning their week-long offensive.

Nevertheless, more than a year of guerrilla war - together with purges launched by the Taraki government - have also taken a heavy toll of the Afghan security forces. A new recruitment campaign is under way, and many of those being drafted are very young men.

The Afghan Army's morale is reported to be low, and there is a shortage of experienced noncommissioned officers and field-grade officers. Desertions are continuing, but not all of the defectors reaching Pakistan join one of the numerous rebel groups to fight on the other side.

A man who walks across the border - sometimes with two or three rifles - can sell his arms and ammunition on the black market and be well fixed. The price of even a Pakistani copy of a Kalishnikov rifle has gone from $1,200 to $2,500 in six months.

This expansion of the arms market here makes it apparent that the guerrillas are not being supplied with large amounts of weapons. Instead, they apparently obtain their arms in the tribal areas, either on the black market or from one of the many Pakistani factories specializing in copying the weapons of other nations. It is possible for anyone to walk into a shop in tribal area, and buy hand grenades, rocket launchers and rifles off the shelf. All that is needed is money.

Attempts by the Pakistani government to crack down on this trade have resulted only in a further increase in prices. CAPTION: Map, no caption, By Richard Furno - The Washington Post