WASHINGTON — The devastating explosions at a Pakistani ammunition dump that killed at least 93 people Sunday were triggered by a coordinated sabotage attack apparently carried out by supporters of the pro-Soviet regime in Afghanistan, sources Monday quoted Pakistani military officials as telling the United States.
The attack, seen by U.S. intelligence analysts as an escalation of the recent Soviet campaign to discourage Pakistan's support for the anti-Soviet rebels in Afghanistan, was touched off by three incendiary devices carried to the scene by trucks bearing Afghan license plates, these sources said.
The devices carried timed fuses and exploded in sequence, the Pakistani officials also have told U.S. officials.
Source of Rebel Arms
The U.S. sources, who refused to be identified, said the explosions wiped out a major source of CIA-supplied tactical assault weapons for the U.S.-backed \o7 moujahedeen \f7 resistance forces battling the Soviet-supported government of Najibullah in Afghanistan.
The weapons lost in the blast--including Stinger anti-aircraft missiles, anti-tank weapons, assault rockets and mines--leave the resistance critically short of the sort of arms needed to mount a final offensive against the Afghan capital of Kabul, two sources said.
American intelligence experts have said publicly that they expect the resistance to topple the Najibullah regime within six months of the planned withdrawal of the estimated 115,000 Soviet troops, scheduled to begin May 15.
Secretary of State George P. Shultz plans to fly to Geneva to sign a four-nation agreement Thursday withdrawing Soviet troops from Afghanistan in return for a U.S. pledge to eventually eliminate arms shipments to the \o7 moujahedeen.\f7
CIA Involved in Deliveries
American weapons shipments to the resistance have been routed by the CIA through Pakistan and stored in ammunition dumps secured by the Pakistani military.
Sunday's apparent sabotage, which occurred as two other blasts rocked a Pakistani ammunition plant and a Saudi Arabian airline office in Pakistan, may be a Soviet warning to Pakistan that it will suffer if it allows continued U.S. arms shipments to Afghanistan, U.S. sources said.
"They've just gotten the first lesson from the Soviets in what happens if you don't control your border," one knowledgeable U.S. source said.
One U.S. official, noting that the resistance already has limited stocks of assault weapons inside Afghanistan, predicted Monday that the ammunition dump blast "will not lead to any immediate crimp, in the near term," in the resistance forces' fighting ability.
Other sources, however, maintained that the weapons destroyed Sunday are not manufactured in quantity and could prove difficult to replace quickly.
In addition, the explosion at a Pakistani ammunition factory in Lahore on Sunday destroyed part of a plant that manufactures bullets for the \o7 moujahedeen, \f7 U.S. sources said.
The apparent sabotage campaign comes on the heels of stern Soviet warnings to Pakistani officials in recent weeks to sign the four-nation Afghan peace accord and to abide by its terms. Sunday's explosions, U.S. sources agreed, do not appear to threaten prospects that Shultz and the Pakistanis will sign the pact, along with the Soviet Union and Afghanistan.
Congress May React Strongly
However, the apparent sabotage may stir strong reaction from Congress, which this year unanimously passed a resolution calling for continued support for the \o7 moujahedeen\f7 until the Soviet Union withdraws its troops and ceases military aid to the Najibullah regime.
One senior U.S. official who insisted on anonymity said that the White House was likely to order an emergency replenishment of the assault weapons lost Sunday and to reassure the Pakistani government that American backing for its role in aiding the resistance would not waver.
However, he said, "this reminds everyone of the danger" that the Soviets would not abide by the agreement. "The Soviets are going to play hardball as they retreat, no doubt about that," he added.
'An Inside Job'
A Pentagon official familiar with the sabotage reports said, "It was an inside job. They must have had someone inside. . . . It was done by the Soviets or their Afghan agents."
He said that the ammunition dump is under the control of Inter-Services Intelligence, the Pakistani intelligence agency, and has tight security. The ISI supervises supplies for the Afghan resistance forces, he said.
"It needs to have been a fairly well-planned operation. We can expect more things like this in the future," he said.
The official, who asked to remain anonymous, said that a sabotage attack would correspond with the Soviets' strategy of undermining Pakistani support for the Afghan rebels to protect the Afghan government as the Soviet troops prepare to withdraw.
Pakistan has served as a dispersal point for weapons that the United States has been funneling to the rebels.
'The Opening Shot'