Pakistan Leader, U.S. Envoy Killed in Plane Explosion : American General Also Dead

President Mohammed Zia ul-Haq and U.S. Ambassador Arnold L. Raphel were killed today when their Pakistani military plane exploded in the eastern part of the country.

The crash apparently also killed U.S. Brig. Gen. Herbert M. Wassom, Pentagon sources said. Wassom, as the chief defense representative to Pakistan, normally would have been traveling with Raphel.

Unconfirmed reports said the plane may have been downed by a missile.

The Pakistan air force C-130 transport plane with 37 people aboard had just taken off from Bahawalpur, 330 miles south of Islamabad, when it exploded about 4:30 p.m., official radio said. A government statement said there were no survivors.

Generals on Board

Besides Zia, Raphel and Wassom, the passengers included several senior Pakistani army generals, the radio said.

Conflicting unofficial reports said the aircraft may have been struck by an anti-aircraft missile. Another version said it collided with a helicopter. Neither Pakistani nor American diplomats could confirm either report.

Another rumor circulating in Islamabad said the plane may have been shot down by India. Bahawalpur is 80 miles west of the border. Pakistani officials refused to comment except to say an investigation was under way.

Indian Prime Minister Rajiv Gandhi said in New Delhi that he was “deeply shocked and distressed” about Zia’s death and sent condolences to his family.

In Washington, State Department spokeswoman Phyllis Oakley said Zia and Raphel went to the remote area in southwestern Pakistan to view a field demonstration of the U.S.-made M-1 tank Pakistan was thinking of buying.

Next in Line

Ghulam Ishaq Khan, chairman of the Pakistani Senate, immediately took over as caretaker president under the Pakistani Constitution.

It was not immediately clear what effect Zia’s death would have on general elections scheduled for Nov. 16.

Zia, 64, took power in a 1977 military coup and ruled with an iron hand under martial law until December, 1985. He began sharing power with a civilian government in early 1986 but fired the government again on May 29, saying it failed to maintain law and order and to enact Islamic law.

The career military officer and U.S. ally strongly supported Afghan guerrillas fighting the Soviet-backed Marxist government of Afghanistan, and he kept up his nation’s military strength to guard borders with India.

Zia took power from Prime Minister Zulfikar Ali Bhutto in 1977, arrested the Cabinet and proclaimed martial law. Two years later, he ordered his predecessor executed on charges of conspiracy to murder. Under his authoritarian rule, mass arrests and floggings were frequent.

Faced a Challenge

In recent months, however, he faced an unprecedented challenge by the country’s increasingly unified political opposition, led by Benazir Bhutto, the daughter of the former prime minister.

Benazir Bhutto, leader of the opposition Pakistan People’s Party, said from her Karachi home today that she was satisfied that constitutional powers were being followed.

“Whatever should have been done has been done. We are sure the changeover will be as smooth as possible,” she said. “Life and death is in the hand of God. We will not say anything,” she said.

Raphel, 45, a native of Troy, N.Y., was named ambassador to Pakistan in January, 1987, by President Reagan.

It was his second assignment to the country. He served there from 1975 to 1978 as political officer in the U.S. Embassy. Raphel also played a key role in negotiations to end the U.S. hostage crisis in Iran in 1981.