President Mohammad Zia ul-Haq, the iron-fisted ruler who died in a suspicious air crash that killed his top military leaders and the U.S. ambassador, was buried Saturday before foreign dignitaries, Afghan rebel chiefs and more than 200,000 other mourners.

As surging crowds chanted the Koranic refrain, "God is great" in bright sunshine, Zia was buried on the sprawling grounds of the Saudi-built Faisal Mosque below the Margala Hills.Zia, 64, U.S. Ambassador Arnold Raphel, U.S. Brig. Gen. Herbert Wassom, and 27 others, including senior pakistan military officials, died Wednesday in the crash of a C-130 military transport plane minutes after takeoff from the eastern city of Bawahalpur.

Hours later, Senate Chairman Ghulam Ishaq Khan assumed the acting presidency under the constitution, declared a national emergency and appointed a committee of senior military and civilian officials to help him run the country of 100 million.

Pakistani officials have said they believe the plane was sabotaged. Pakistani experts reportedly believe the control system was tampered with, discounting preliminary reports the aircraft - identified by a U.S. official as Zia's personal plane - exploded in-flight.

But another U.S. official quoted Secretary of State George Shultz as telling Ghulam in a meeting Saturday morning that "there is no basis at this time for speculation as to the cause."

In a statement after their talks, Shultz said he had reaffirmed to Ghulam that "the U.S.-Pakistani relationship rests on longstanding shared purposes and common goals" and that Washington is "prepared to render any help you need during this time of tragedy and sorrow."

A sealed wooden coffin bearing Zia's remains was flown by helicopter from his residence in Rawalpindi to the modern cream-colored presidential palace in the twin city of Islamabad.

The aircraft, flanked by two other helicopters, descended onto the plush lawn of the mansion where Zia never lived. An honor guard stood at attention, the sun glinting from the soldiers' buckles and polished weapons.

Hundreds of mourners who flocked to the palace watched as grim-faced army officers carried the coffin into the cavernous receiving hall, where it was put on a platform. Zia's weeping widow and other family members then filed by.

With Zia's military cap sitting on the top, the coffin was again borne outside and placed under a canopy. His brother Iman ul-Haq, his face glistening with tears, read from the Moslem holy book, the Koran, as mourners walked past, crying women sprinkling the coffin with perfume.

The coffin was put in a army ambulance, which sped from the palace preceded by a motorcycle escort down a broad avenue toward the Faisal Mosque, the world's second largest Islamic shrine and opened by Zia in June.

More than 200,000 people flooded the area, swarmed around the white mosque and stood on its roof and minarets, many weeping and chanting "Zia is a martyr."

At the approach road entry, Zia's casket was transferred onto a gun carriage. About 40 servicemen and 20 presidential security force personnel hauled the carriage by ropes slowly up the road, followed by a man bearing a huge portrait of the late president.

The crowds surged from the rear and sides, prompting soldiers and police to move to the processions flanks to protect it as it entered the mosque gates.

A canopy-covered grave on the mosques front lawn was flanked by Pakistani officials, family members and dignitaries from about 70 nations, including Shultz.

Also present were heads of six of the seven mainstream Afghan guerrilla groups to whom Zia funneled U.S. weapons, and a three-member Soviet delegation. The six spoke briefly with Shultz and were embraced by Zia's successor as military head, Gen. Aslam Baig.