The U.S. Command refused to comment on the continuation of its heavy bombing of the Hanoi-Haiphong area yesterday. The bombing followed the loss of two B52 bombers and an F111 fighter jet over North Vietnam on Monday.

The "no comment" issued by the U.S. Command left open the possibility that more aircraft had been lost in yesterday's raids. The command customarily withholds such information when search and rescue efforts are under way.

AP sources said that the U.S. Command news blackout was ordered by President Nixon.

In the Soviet Union, the American bombing escalation was termed heartless and brutal. In a statement issued by the official news agency Taw, the Soviet said. "The action can only complicate the situation, prolong the blood shed and make is more difficult to reach as agreement."

In the United States, the stock market improved from Monday's 14-point plunge, but continues to be weak. Monte a Gordon, a stock market spokesman, said. "The market is tense and dissatisfied with the Vietnam developments.