Diplomacy Flying into a Tight Corner

Only three months ago, the Pakistani border town of Teri Mangal bustled with a busy bazaar and a steady flow of Afghan mujahedin rebels on their way to or from the fighting in Afghanistan. Today Teri Mangal is deserted. On March 23, Soviet-built Afghan MiGs roared across the frontier, demolishing many of the shops that sold arms to the guerrillas and leveling the simple clapboard flophouses where they bedded down for the night. The raid claimed more than 80 lives.

The Teri Mangal bombing was the first widely reported result of a Soviet and Afghan air offensive that began late last year. The targets: Afghan rebel staging areas inside Pakistan. So far this year more than 100 aerial bomb and rocket attacks inside Pakistan have claimed at least 297 lives. During all of 1986, only about 24 people were killed in similar raids. The increase in the number of strikes prompted Pakistan to send President Reagan an "extremely urgent" request for U.S. radar surveillance planes to direct Pakistani F-16s against intruders along the country's 1,400-mile border with Afghanistan.

With little public fanfare, the U.S. quickly agreed to supply the planes, which go under the acronym AWACS, for Airborne Warning and Control System. But complications in both the U.S. and Pakistan in recent weeks have dampened hopes of delivering them anytime soon. The main stumbling block is that Washington and Islamabad have been unable to agree on what type of plane would be most suitable. Washington has also been taken aback by some troubling consequences of the decision, including the possibility that it may put American soldiers in danger -- and involve the U.S. more directly than ever in the Afghan war.

The chain of events that brought the Reagan Administration to the current impasse began in early 1986. At that time Washington pressured Islamabad to permit the Afghan guerrillas in Pakistan's border province to receive Stinger antiaircraft missiles from the U.S. Pakistani President Mohammad Zia ul-Haq reluctantly went along, despite a warning from the Soviet Union that Pakistan would pay a high price. By last November, mujahedin equipped with Stingers were shooting down an average of one Soviet or Afghan aircraft a day. Last week, according to Radio Kabul, the rebels struck again, downing an Afghan transport plane and reportedly killing 53 people. Shortly after the weapons began to reach the rebels last fall, Afghan air strikes inside Pakistan intensified. Now Pakistan insists that the U.S. is responsible for its defense. The Reagan Administration is concerned that if it turns its back on Islamabad, Zia might do the same to the rebels. Says Noor Husain, a veteran Pakistani defense analyst: "The U.S. has got itself in a tight corner."

< At the moment, the U.S. and Pakistan are discussing which craft Islamabad should buy. Pakistan wants to buy three Boeing E-3A Sentries. The jet, which the U.S. deploys on the NATO front and in other key strategic areas, is a top- of-the-line technical marvel whose exact capabilities are classified. But Washington says it has no Sentries to spare, and has offered instead the much less sophisticated Grumman E-2C Hawkeye. Capable of tracking more than 600 targets at a range of 300 miles, the propeller-driven Hawkeye is slower and more vulnerable to attack than the Sentry.