PESHAWAR, PAKISTAN — FOR the past week, a steady stream of ramshackle vans and trucks has been stopping outside the Al-Fawzan Surgical Hospital for Afghans. These makeshift ambulances have brought scores of wounded Afghan guerrillas from the fierce battle under way for the strategic town of Jalalabad, about 35 miles away, inside Afghanistan.
The 110-bed hospital, opened in this Pakistani border town in 1985, is jammed with injured mujahideen from the heaviest fighting in the nine-year Afghan war. New beds are being added daily.
``This is the biggest emergency so far,'' says Zahid Al-Shaikh Mohammed, regional head of the Islamic Call Society, which runs the hospital.
``Before Jalalabad, the injuries were mainly from mines because the mujahideen were fighting from afar,'' he continues. ``Now they are suffering from bullets and shrapnel wounds. That means the war has moved closer.''
FOR nine years the Afghan guerrillas waged a hit-and-run war in the countryside that finally forced the withdrawal of about 115,000 Soviet troops. Now the mujahideen have launched their first frontal assault against a major city in an effort to crack the Soviet-supported regime of President Najibullah.
The mujahideen hope to take Jalalabad as a stepping stone to the capital, Kabul, and a foothold for their fledgling government-in-exile based in Peshawar.
In a swirl of conflicting reports, the Kabul regime claims it has repulsed the mujahideen attack while resistance leaders say about 15,000 mujahideen have the city surrounded.
Both sides say that civilian casualties are heavy and Pakistani officials in Peshawar say that 15,000 Afghans are fleeing across the border, swelling the more than 3 million refugees now sheltered in Pakistan.
The Jalalabad attack follows the Feb. 15 departure of Soviet troops and several weeks of bickering among the rival mujahideen groups based in Pakistan and Iran over leadership of the interim government.
``If we capture Jalalabad, then we can capture other cities as well,'' says Sibghatullah Mojaddidi, president of the ``interim'' resistance government in an interview. ``Psychologically, it will have a very bad effect on the puppet regime in Kabul.''
The assault also could help win credibility for the new government among the United States, Saudi Arabia and other resistance supporters, observers here say. The US Congress is considering a new aid package for Pakistan, the conduit for Afghan aid, and the would-be government is seeking recognition at a meeting of foreign ministers from 45 Islamic countries in Saudi Arabia.
``They have to have an impact inside,'' says a Western diplomat. ``Administering a city the size of Jalalabad and sustaining it as a capital will be difficult.''
Several analysts agree. Mr. Mojaddidi says the mujahideen delayed the attack on Jalalabad because they had hoped mass defections in the Afghan Army and government would lead to the fall of the Najibullah regime. But he charges that some factions tried ``to deceive us.''
Jalalabad can readily receive food supplies from Pakistan and is on the main highway to Kabul. But it is well-defended and has a large civilian population that is split by traditional differences. These splits could trigger a backlash and a spate of atrocities, some Western diplomats say.
Mujahideen leaders say that warnings have been issued to the people in Jalalabad which has come under heavy bombing from Kabul. The intense fighting has sent thousands fleeing on foot, according to Pakistani and mujahideen officials.
In Peshawar, officials are braced for a new wave of refugees.
Ahmad Shah, a 29-year-old fighter, recently returned from Jalalabad with the bodies of three mujahideen fighters.
``The bombing is driving the civilians out,'' he says. ``I am afraid that many are being killed.''
Mujahideen leaders say the interim government has to be shifted inside Afghanistan to make an impact. Some American officials say the US is anxious to begin channeling aid through that government and not the various political parties in Peshawar.
Meanwhile, even the interim government will likely have to keep moving its locations and meetings to avert bombing raids, Mojaddidi says.
Still, the new government has yet to gain the support of the Iranian-backed guerrilla groups. They boycotted the recent shura (consultive assembly) which chose the government's leaders. Some of these men admit that the new government, even if and when it succeeds in taking Kabul, will be decentralized - with most of the power being distributed along the diverse and traditional tribal lines of authority.