DACCA, June 25. - People talk with foreigners in a whisper and keep looking behind them to see if any one is listening. Soldiers and special police - brought from West Pakistan, more than 1,000 miles away - stop and search cars and buses and people carrying bundles.

Arrests are made and denied. When families ask the martial-law authorities what has happened to a son or father, the army replies that he was released after questioning and that if he has not returned home, then maybe he has fled to India.

Many people listen to the clandestine Bangla Desh (Bengal Nation) radio every day. although the penalties are severe.

This is the nervous and unhappy flavor of Dacca, capital of East Pakistan, three months after the army launched its offensive to try to crush the Bengali autonomy movement throughout the province.

The army is clearly in control of this city, but "normality" - the word the Government uses to describe conditions here - does not exist.

Dacca today can best be described as a city under the occupation of a military force that rules by strength, intimidation and terror, but which has been unable to revive an effective civil administration.

Only about half of Dacca's million and a half people are here. Most of the others have fled to the interior or to India and many thousands - no one knows the exact number - have been killed by the army.

Although people are trickling back to the city, a great many shops are still closed. Most of those that open close before dark out of fear of looting and harassment by the military and those civilians working with the military.

RUBBLE CLEARED AWAY

Traffic is thin. At times of day that were once rush hours, cars move with relative ease through the narrow streets of the old city. In the past they would have been delayed for as long as an hour.

This week, for the first time since the army assault began on March 25, the Government has permitted foreign newsmen to enter East Pakistan and travel around unescorted.

Much of the rubble from the attack, carried out with tanks and rockets and other heavy weapons. has been cleaned up by the authorities. Enough remains, however, to suggest the havoc that prevailed in the city.

The foreign community here has come to refer wryly to the razed areas as "Punjabi urban renewal" - a reference to the preponderance of Punjabis, or West Pakistanis, in the army.

The bulk of the destruction is in the old city, the home of most of Dacca's poor. They were stanch supporters of the Awami League party, which won a majority in the election last December for a National Assembly on a platform of more self-rule for East Pakistan. The party is now banned.

ONLY DEBRIS REMAINS

Block upon block once crowded with flimsy huts with tin roofs are now long, empty, dusty fields. Only a heap of debris here and there indicates anything once stood there.

Some brick and cement buildings that were too badly damaged to repair are being torn down by the Government to remove all evidence of the holocaust.

The authorities are in fact doing a considerable amount of face-lifting. Bulldozers push the wreckage off these charred plains. Bullet and shell gouges in nearby houses are being patched and painted over.

There has been patching and painting also at the university and at the Bengali police barracks - two of the army's special targets. But one quarter-mile stretch of older, one-story police barracks still looks as it did on the morning after the attack - burned and smashed to the ground by heavy fire. An estimated 700 Bengali policemen were killed in that army attack.

In the old city the authorities are erecting new brick shops on some of the razed areas and leasing them to businessmen. One area of wholesale shops that was burned out is being rebuilt by the original owners.

CRUSH INDIA SIGNS

The atmosphere here, as it is everywhere else, is of fear. Some shopkeepers, to keep the army from harassing them, have displayed signs in their window that read "Crush India." Everybody flies the Pakistani flag.

Few people will talk openly on the streets, but as the visitor's car passes alongside, they whisper things through the open car window. "All was burned," one old man said out of the side of his mouth.

Many Hindu shopkeepers, most of whom sold sweets, have either fled or been killed. Their shops have been given to non-Bengali moslems and others who are siding with the army.

HOUSES FOR THE LOYAL

The Hindu minority, in particular, has been harassed by the army. The West Pakistani Moslem establishment has long considered the Hindus untrustworthy people whose real allegiance has been with predominantly Hindu India. Of the six million East Pakistanis who have fled to India to escape the army, four million or more are Hindus.

The authorities are demolishing Hindu temples, regardless of whether there are any Hindus to use them.

The houses of people who have fled - whether Hindus or members of the Moslem majority - are being given to "loyal" citizens. In some cases, people who are still here have been forced out of their homes.

Auto license plates have been changed from Bengali script to English, as part of the campaign to suppress Bengali culture.

Not too many soldiers are visible on the streets, but their substitutes are policemen from West Pakistan, dressed in charcoal-colored shirts and berets. They spend much of their time searching vehicles, presumably for homemade bombs and other weapons.

Bengali guerrillas have been throwing bombs and carrying out other terrorist activities in Dacca, but the insurgency is still sporadic and not well organized. Reports continue to circulate through the city of the army's picking up Bengalis for interrogation, and sometimes killing them.

Many of the reports, though widely believed in the foreign community, are hard to confirm firsthand. Some, however are verified by eyewitness evidence.

One senior civil servant and his entire family were taken recently to the army cantonment for questioning. All were later released except for his son. His father has been unable to find out what has happened to his son, or even what he was charged with.

"Now you will see everything," a young Bengali whispered to a foreign newsman in a downtown shop. "What they have done, you cannot know. Women, everything. I am a Hindu and I have changed by name to a Christian one and have put my family in a Christian house. We are grateful you have come. We are praying you can help us."