Washington — As Soviet forces strengthen their positions in Afghanistan, the Carter administration faces the worrisome problem of getting adequate military aid to Gen. Zia ul-Haq's forces in neighboring Pakistan.
General Zia's scornful rejection of a $400 million US economic and military aid package as "peanuts," followed by more recent indications that Pakistan would take the economic half of hte package, while leaving the military half, have complicated matters.
So has new uncertainty about US foreign aid levels, in the light of President Carter's order for a balanced federal budget and concern that American equipment stockpiles may be insufficient for domestic use in wartime, let alone for major new commitments to friends like Pakistan.
Mainly because the Carter administration was unwilling to commit US ground forces to fight any Soviet incursion, there is no certainty of how much or how soon any meaningful Western military help could reach the Pakistanis, American military observers now acknowledge.
Observers who accompanied US National Security Adviser Zbigniew Brzezinski on his recent rifle-brandishing visit to Pakistan's uneasy Khyber Pass frontier with Afghanistan say Pakistanis, from the top level down to lieutenants and captains, pledged to the American mission to fight to the last against any Soviet attack -- provided the US was willing to say when its forces would arrive on the scene to help them.
Mr. Brzezinski was unable to do this. The Carter administration, US defense analysts say, wants to defend the Persian Gulf area as the President promised last Jan. 23, but without committing any American forces to a land war in Asia.
General Zia and his advisers, say sources close to their thinking, now seek up to $2 billion to totally rebuild the Pakistani armed forces, reorienting them away from their old enemy, India, and toward defense of the Afghan borders.
Equipment would be purchased from France, the US, or others able to sell it. So far, only Saudi Arabia has indicated it might help with $700 million or $800 million. But the Saudis are reluctant to work in any aid consortium that includes their Arab rival, Egypt, which has offered to help to train and arm the Afghan rebels.
General Zia is expected shortly to install a new government with former Air Force commander Gen. Yaqub Khan, presently ambassador to Moscow, as foreign minister, with Aga Shahi, General Zia's present security affairs adviser, keeping his job.
Both are expected to continue overtures toward the Soviets to quit Afghanistan, while seeking large arms packages and financing from the Arabs and Western Europe.
Pakistani fears about the Soviets have been heightened by a recent probing, prespring offensive by helicopter-borne forces against Afghan Muslim rebels in the Kunar Valley, adjoining the border north and east of the Khyber Pass.
Rebels and their arms have crossed this frontier with some freedom from their Pakistan bases. The valley would be the logical place for any massive Soviet efforts to seal the border.
The Soviets reportedly took up to 100 casualties in the Kunar operation, with indecisive results. The Soviet high command near Kabul now has begun to appoint separate task forces for the expected spring offensives.
Afghan troops still cooperating with the Russian force of 100,000 now inside or near Afghanistan recently requested new chemical warfare munitions from the Soviets.
What the rebels now need most urgently, say military analysts, are gas masks, handheld antiaircraft missiles for use against the Soviet MI-24 helicopter gunships, light weapons and ammunitions, rocket launchers, mines, and emergency food and medical supplies -- the sort of equipment Moscow sent to North Vietnam, which helped the Vietnamese win the war in Indochina against the US.
Western analysts believe that India will object even more strongly to the Pakistani desire for major rearmament than it did to the earlier US offer of smaller defensive means.
Another obstacle is what a recent report of the Association of the US Army (AUSA) called growing concern that the US simply cannot spare enough equipment for Pakistan and still meet other major overseas military commitments, such as those to Israel and Turkey.
The need for economy in the US defense and foreign aid budgets means that US defense industry may have to cut production.