WASHINGTON, Dec. 9—The State Department said today that a “neutral zone” had been established in Dacca to protect nearly 500 foreigners, including some 70 Americans, awaiting evacuation by air from the besieged city.

A spokesman said that the creation of the “neutral zone” was requested by the United Nations and the United States in expectation of ground fighting in Dacca as Indian troops approached.

The zone, comprising the Intercontinental Hotel, the Holy Family Hospital and the headquarters of the United Nations relief operations, is to serve as an assembly area for the foreigners before they are taken to the airport to be flown out.

Citing diplomatic dispatches from Dacca, United States officials said two British and two Canadian C‐130 transports would attempt the evacuation tomorrow night and Saturday during a truce in the air attacks on the city's airports that India promised earlier today.