ISLAMABAD, Pakistan — President Zia ul-Haq, Pakistan's military ruler, was killed Wednesday along with U.S. Ambassador Arnold L. Raphel, the senior U.S. military attache and 10 senior Pakistani generals when the president's plane exploded in midair moments after takeoff from a remote desert town. The government said it did not rule out the possibility of sabotage.
After a marathon Cabinet meeting that ended just before midnight local time, a state of emergency was declared throughout the country and the chairman of Pakistan's national Senate, Ghulam Ishaq Khan, was installed as president.
In a televised address early today to his stunned nation of more than 100 million, Ishaq Khan vowed to hold national elections as scheduled on Nov. 16 and announced the formation of an emergency ruling council dominated by civilians.
"Our faith in democracy will not be shaken," declared Ishaq Khan, who is Pakistan's first civilian leader since Zia, 64, seized power in a military coup 11 years ago. "We will proceed on the shining path of democracy with all determination."
The government ordered an immediate investigation into the "tragic accident," which claimed a total of 37 lives. And "the possibility of sabotage cannot be ruled out," Ishaq Khan declared, without naming any potential suspects, either within his politically troubled nation--one of America's key strategic allies in Asia--or on its two embattled borders.
Ishaq Khan added, "It is now all the more necessary for us to watch carefully the unholy designs of our enemies."
Despite the sudden death of Zia, a sometimes ruthless military leader who ran Pakistan single-handedly for more than a decade, the nation remained peaceful throughout the night, with no celebrations and few tears shed publicly.
Details of the explosion remained sketchy. Official reports said the Pakistani air force C-130 transport plane blew up a few minutes after takeoff from the town of Bahawalpur, 350 miles south of the capital of Islamabad.
Initial, unconfirmed reports suggested that the plane had been hit by a missile or had collided in midair with another aircraft. But the Pakistani government later refused to confirm those reports.
Raphel, 45, was a career Foreign Service officer who had been involved in diplomacy in Southwest Asia for more than 20 years, beginning with his assignment to Esfahan, Iran, in 1967. During the Iran hostage crisis of 1979-81, he was deeply involved in efforts to secure the U.S. captives' release.
Raphel was one of the main architects of U.S. policy toward Afghanistan in the wake of the Soviet invasion of 1979 and was named ambassador to Pakistan last year.
Also killed in the crash Wednesday was the senior U.S. military attache to Pakistan, Brig. Gen. Herbert M. Wassom, 49, the State Department announced in Washington. He and Raphel were the only Americans aboard the plane.
In addition, the chairman of Pakistan's joint chiefs of staff, Gen. Akhtar Abdur Rahman, and Lt. Gen. Mian Mohammed Afzaal, the deputy army chief of staff, were among the dead. The victims also included three major generals, five brigadier generals and a number of other officers, as well as 13 crew members.
The U.S. and Pakistani officials had spent the day in Bahawalpur observing the testing of the new U.S. M-1 Abrams tank, which Pakistan is considering for its armed forces.
Eyewitnesses near the Bahawalpur airport said thousands of villagers rushed toward the crash site within minutes of the explosion, but military and police authorities immediately cordoned off the area.
An official report issued today said investigators were still searching the site for remains. The wreckage was "scattered over a very large area," it stated, and a senior government official said that no official funeral plans would be made until the site was thoroughly examined.
10 Days of Mourning
Meanwhile, flags were lowered to half-staff today as Pakistan began 10 days of official mourning.
In Santa Barbara, where President Reagan is on vacation, White House spokesman Marlin Fitzwater said: "The President of course passes along his deepest sympathies to the people of Pakistan, to the families of the ambassador and President Zia and all the people on the aircraft. But at this point we are still lacking details of what happened."
Raphel's wife, Nancy, is well known to the Reagans and particularly is a friend of First Lady Nancy Reagan, Fitzwater said, adding: "So there is a great personal feeling of loss."
Vice President George Bush said at a news conference in New Orleans that Pakistan and the United States "have a very special relationship, and the loss of Gen. Zia is a great tragedy." He called Raphel "an outstanding ambassador."
Also in New Orleans, Secretary of State George P. Shultz called for a moment of silence at a luncheon he was attending. He called Raphel "a man of immense ability who'd been doing a superb job."