WASHINGTON, Dec. 15—A United States naval task force of eight ships, led by the nuclear aircraft carrier Enterprise and transporting 2,000 marines, steamed northwest in the Bay of Bengal today toward India and East Pakistan.

Spokesmen at the White House and the State and Defense departments refused to comment on the fleet movements or their purpose. But authoritative Administration officials disclosed to reporters that the squadron had been ordered into the area on a combined political and humanitarian mission.

The State Department said the United States stood ready to evacuate 182 Americans in Dacca, if needed, by “sea or by air,” although it declined to link publicly such an evacuation operation with the naval movement.

Informants said the squadron was steaming northwest at 16 to 20 knots and its position today was reported as 1,200 nautical miles southeast of East Pakistan. If the flotilla maintained its present speed, Friday morning would be the earliest it could reach a position to evacuate the Americana from Dacca, if such a move was required.

The political mission of the squadron, which includes the helicopter carrier Tripoli and eight destroyers, was described by these officials as a “show of force” by the United States for the benefit of both India and the Soviet Union.

The task force was ordered yesterday to transit the Malacca Strait into the Bay of Bengal because, officials said, it appeared to the Nixon Administration that a United States armed presence might be a stabilizing influence in the area as the Pakistani resistance in East Pakistan was collapsing and other Indian intentions toward. Pakistan remained uncertain.

An increase in Soviet naval strength in the Indian Ocean In recent weeks was cited as another reason for the decision to shift the squadron from Indochina waters.

Officials, who explained in private conversations the latest developments in American policy, said that it was a matter of prudence as well as of United States prestige to avoid being overshadowed by the Soviet Union in naval strength off the Indian subcontinent.

No Reply by India

The State Department spokesman, Robert J. McCloskey, noted that India had not replied to a United States request for assurances that she would not move on West Pakistan after defeating the Pakistanis in the East.

As all Government spokesmen did today, Mr. McCloskey refused to publicly discuss United States naval movements. But other authoritative sources said the concern that India might move against West Pakistan was among the reasons for the naval move.

Mr. McCloskey said that no decision had been made on evacuating 165 American citizens and 17 Government employes who stayed in Dacca when 125 Americans were flown out Sunday.

But he emphasized that the United States would be “in a position to do that” if necessary and could act on short notice.

Administration sources insisted that there were no plans by the United States, as suggested yesterday at a news conference here by the Indian Ambassador, Lakshmi Kant Jha, to use the naval squadron to help evacuate Pakistani troops from East Pakistan.

There were indications in diplomatic quarters, however, that the United States is seeking, in a variety of ways, to encourage arrangements under which India would accept a cease‐fire in East Pakistan and allow the Pakistani troops to leave, with their weapons, for West Pakistan.

‘Confusing Traffic’ Noted

It appeared that proposals to that effect were part of what State Department officials described this evening as “highly confusing traffic” in telegrams between the American Consulate General in Dacca, the American Embassy in New Delhi, the United Nations in New York and the department here.

Officials confirmed that Lieut. Gen. A. A. K. Niazi, the military commander in East Pakistan, requested the American Consulate last night to relay his cease‐fire proposal to the Indian authorities. They said General Niazi's message was forwarded immediately to the American Embassy in New Delhi and given to the Indians.

Mr. McCloskey and other American officials emphasized, however, that the United States was not acting as a mediator but confining itself to the role of a communications channel.

The Government here refused to make public the text of General Niazi's cease‐fire proposal, even though the Indian answer — demanding a surrender — was published in New Delhi.

The reason for keeping the Niazi message confidential was understood to he its contents, discussing means of repatriating Pakistani troops with their weapons.

On the question of the fate of the Pakistani troops trapped in the East. Mr. McCloskey insisted that for the United States the first priority was a ceasefire and then relief measures for the victims of the fighting.