An organization representing Americans of Arab descent yesterday called for a congressional investigation into the United States' role in events leading up to and during the massacre of Palestinian civilians in West Beirut last weekend.

The American-Arab Anti-Discrimination Committee (ADC), which promotes an Arab perspective on events in the Middle East, has asked Sen. Charles Percy (R-Ill.), chairman of the Senate Foreign Relations Committee, and Rep. Clement Zablocki (D-Wis.), chairman of the House Foreign Relations Committee, to investigate why U.S. Marines were withdrawn, "in spite of U.S. commitments to guarantee the safety of Lebanese and Palestinian civilians and institutions in Beirut."

In a letter to the two legislators, ADC cited reports that the U.S. Embassy in Beirut was saying "nothing unusual" was happening in the refugee camps last Friday, 15 hours after the massacre reportedly began. It also alleged that Israeli troops "looted Palestinian and Lebanese research institutions, carrying away priceless archives."

ADC also charged that "Israel has repeatedly and flagrantly violated U.S. public law" by using "U.S. weapons to invade, bomb and occupy Lebanon and, most recently, to invade West Beirut."

Asked yesterday when the U.S. Embassy in Beirut knew what was happening in the refugee camps, a State Department spokesman said the embassy received "fragmentary reports" about events on Friday, but that the first time an embassy staff person was able to enter the camps was on Saturday morning.

He refused to say if anyone from the embassy staff had tried to enter the camps sooner, or to give the exact chronology of how and when the embassy learned of the massacre.

Meanwhile, for the second day this week, members of the Arab Womens' Council picketed in front of the White House to express their anger at the killings of Palestinian civilians and demand the departure of Israeli forces from Lebanon.

About 40 women, some of them the wives of ambassadors from Arab states, stood in four-hour shifts, carrying a large banner that read: "No More Massacres! Get Israel out of Lebanon Now!"

A memorial service for victims of the massacre at the two refugee camps will be held this afternoon at the Sheraton-Washington Hotel by the Arab Womens Council, ADC and the Palestine Congress of North America, a group sympathetic to the Palestine Liberation Organization.