Not so, Washington kept insisting. Deputy Secretary of State Strobe Talbott formally assured Britain and France that the United States was not helping the Muslims. The Pentagon and the CIA denied they were sharing intelligence. Washington continued to obey the arms embargo, though it no longer helped to enforce it. The congressional options briefing had been required by the same law that compelled Bill Clinton to stop enforcing the embargo; the Pentagon warily pointed out that arms aid to the Muslims would require U.S. trainers on the ground and could make things worse in Bosnia. But still, as the Europeans suspected, something was indeed going on.

Providing weapons and intelligence isn’t the only way to help the Muslims against the Serbian aggressors. As part of its effort to encourage a negotiated settlement, Washington has been promoting an effective military alliance between the Muslims and the third ethnic force in Bosnia, the Croats. For that purpose, official U.S. visitors to Bosnia this year have included Defense Secretary William Perry and retired Gen. John Galvin, who played a key role in organizing the alliance.

The Bosnians also are quite capable of helping themselves. Last week, at a mysterious airstrip near Zenica, reporters spotted two G-4 Super Galeb trainers converted to fighter planes, which the Bosnians apparently obtained from the former Yugoslav arsenal. And they seem to have hired a few American mercenaries. Tom Slizewski, executive editor of Soldier of Fortune magazine, says he has ““firsthand knowledge’’ of some adventurers who have signed up.

Bosnia’s recent successes on the battlefield provoked a Serb counteroffensive against the city of Bihac, supposedly a ““safe area’’ protected by the United Nations. Twice last week, Serb jets attacked the Muslim enclave, dropping napalm and cluster bombs. That prompted the U.N. Security Council to authorize NATO airstrikes against the Serbs if they do it again. If safe areas turn out to be unsafe, the Clinton administration may come under new pressure to give the Muslims more than just political support.

PHOTO: Death in Sarajevo: U.N. firefighters with a 7-year-old boy killed by a Serbian sniper