Secretary of State James A. Baker III Thursday arranged to meet with Vietnam's foreign minister, accelerating a U.S. drive to improve relations with a onetime bitter Communist foe.

The two main topics Baker will take up with Nguyen Co Thach, who is also deputy prime minister, are efforts to form a new government in Cambodia and the fate of more than 2,400 Americans missing since the Indo-China wars.Some 1,700 are missing in Vietnam, where the United States fought futilely to prevent Communists from the north from taking over the south.

The meeting will be held Saturday for about 30 minutes, Margaret D. Tutwiler, the State Department spokeswoman, said in an announcement in New York, where Baker is meeting with Soviet Foreign Minister Eduard A. Shevardnadze.

It will be the highest level U.S. session with a Vietnamese official since the 1973 Paris peace talks brought the war to a close.