ISLAMABAD, Pakistan (AP) _ Pakistan began three days of official mourning today after an ammunition depot blast that officials said killed 93 people and wounded 1,100. Newspapers today reported more than 100 dead.

Hundreds of people who lived close to the army depot, located between Islamabad and Rawalpindi, remained unaccounted for after Sunday's blast.

Pakistan Radio broadcast appeals for missing people, and Prime Minister Mohammad Khan Junejo ordered the removal of dangerous ordnance from populated areas.

Pakistanis repaired their cinderblock houses or sifted through the ruins in search of salvageable household goods. Rescuers continued their search for victims.

Police and army troops patrolled the dusty streets as entire families roamed the worst-hit areas to view the damage and search for loved ones.

Officials said about 100 bomb disposal teams were clearing an estimated 6,500 different kinds of projectiles that lay strewn among the two cities.

President Mohammad Zia Ul-haq today refused to speculate on the cause of a fire which reportedly ignited the ammunition dump between the twin cities of Islamabad and Rawalpindi, showering both with rockets, grenades and artillery shells.

As to reports that the ordnance was earmarked for Afghan Moslem insurgents, Zia said: ''It's nothing but speculation - a high measure of speculation.''

Eyewitnesses reported seeing burning trucks near the depot bearing Afghan license plates.

Pakistan backs the guerrillas in their struggle against Kabul's Marxist government and the estimated 115,000 Soviet troops who back it. It also serves as a conduit for U.S. military aid to the insurgents.

Zia said the dead included seven army soldiers. He said 60 percent of the total number of wounded had been treated and released.

Official sources said the blast was caused by a fire but Western diplomats, speaking on condition of anonymity, said they had heard reports of a possible military coup attempt. Some embassies said they received anonymous telephone calls warning of a terrorist bombing shortly before the facility blew up.

The explosions, which occurred during morning rush hour Sunday, sent missiles and grenades slamming into buildings, buses and cars in the capital and the adjacent city of Rawalpindi.

The initial blast flattened most buildings within 200 yards of the depot and sprayed shrapnel and unexploded projectiles for more than a six-mile radius.

There were no reports of casualties among the estimated 25,000 foreigners who live in the capital.

Also Sunday, eight people were killed in a fire at an arms factory near Lahore, 140 miles south of Islamabad, and three people were injured by a bomb that exploded in Karachi, 650 miles southwest of Islamabad. Authorities said those two incidents appeared unrelated to the disaster in Islamabad.

In India, riots broke out today when mobs of students tried to close shops in northern Kashmir state to show sympathy for the victims of Sunday's explosion at the ammunition depot.

The United News of India reported that scores were injured when police clashed with the students.

The news agency said the mobs set fire to an army jeep, burned down a liquor store and stoned passing vehicles.

India and Pakistan have fought three wars, two of them over Kashmir. Some of the Moslems, who predominate in Kashmir state, want to unite with Pakistan.

There have been numerous explosions and bomb attacks in Pakistan during the past two years that have killed about 300 people and injured hundreds.

The government frequently has blamed attacks on agents of Afghanistan's communist government, which has denounced Pakistani support of Afghan rebels.

Many bombings have also occurred during violent demonstrations by opposition parties demanding the resignation of President Zia.

The ammunition dump is located at Faizabad Crossing, near the capital's border with Rawalpindi. Army troops and riot police were deployed around Islamabad to seal off dangerous roads and prevent panic.

One of the dead was identified as a lawmaker and former minister of production and public works, Khaqan Abbasi, whose car was hit by a rocket.

Islamabad is a city of 500,000 built during the 1960s to replace Karachi as the capital. In addition to government buildings, it contains about 85 foreign embassies and several offices of U.N. and other international relief agencies.