WASHINGTON -- Investigators at the international war crimes tribunal in The Hague, Netherlands, have concluded that the Croatian army carried out summary executions, indiscriminate shelling of civilian populations and "ethnic cleansing" during a 1995 assault that was a turning point in the Balkan wars, according to tribunal documents.

The investigators have recommended that three Croatian generals be indicted, and a U.S. official said last week that the indictments could come within a few weeks.The indictments would be the first of Croatian army officers for actions in the Balkan wars of 1991 to 1995, which first pitted an independence-seeking Croatia against rebel Serbs and Serbia proper and then moved to Bosnia.

Any indictment of Croatian generals could prove politically troublesome for the Clinton administration, which has a delicate relationship with Croatia, a U.S. ally with a poor human-rights record in preserving the peace in Bosnia.

The August 1995 Croatian offensive, which drove some 100,000 Serbs from a large swath of Croatia over four days, was carried out with the tacit blessing of the United States by a Croatian army that had been schooled in part by a group of retired U.S. military officers. Questions remain about the full extent of U.S. involvement.

In the course of the three-year investigation into the assault, the United States has failed to provide critical evidence requested by the tribunal, according to tribunal documents and officials, adding to suspicion among some there that Washington is uneasy about the investigation.

To date, the war crimes tribunal, set up by the United Nations in 1993, has indicted 83 people, most of them Serbs. Its chief prosecutor, Louise Arbour, will ultimately decide whether the indictments should be issued.

The investigators have also recently begun looking into whether the Croatian president, Franjo Tudjman, should be held responsible under international law for his role in the assault, tribunal and U.S. officials said.

At the same time, the investigators have stepped up an inquiry focusing on Slobodan Milosevic, the Yugoslav leader, who is widely seen as the architect of the Balkan wars. U.S. officials and tribunal staff said that a special team to investigate Milosevic was set up at the tribunal in October.