ZAGREB, CROATIA — A DESPERATE Western desire for a peace deal in the former Yugoslavia may be affecting how aggressively investigations into alleged atrocities in Bosnia and Croatia are being pursued. UN officials say the investigation into alleged atrocities committed by the Croatian Army against rebel Serbs earlier this month is receiving little support from the international community. And officials from the International Committee of the Red Cross and United Nations say they are trying to gain access to Bosnian sites of alleged atrocities, but Bosnian Serb authorities continue to block them. Between 4,000 and 6,000 Muslims are missing from the fallen UN ''safe areas'' of Srebrenica and Zepa. An Aug.18 report in the Monitor cited on-the-ground evidence that hundreds of Muslim prisoners were massacred in the eastern Bosnian village of Nova Kasaba in July. ''If the international community doesn't want to put pressure on the Bosnian Serbs [and Croatia] to allow access, there is little we can do,'' says a UN investigator. ''No one is going to take anything away from the Serbs or the Croats because they have the [military] power here.'' UN officials say that with a new American peace initiative for the region and Washington's strong backing of Croatia as a counterbalance to Serbia, chances are low that intense international pressure will be brought to bear on either Croatia, the Bosnian Serbs, or Serbia to allow a full investigation of alleged atrocities. ''We've been effectively muzzled,'' says a Zagreb-based UN official. ''You won't be hearing anything else about burning houses and dead bodies [in Croatia] from here.'' The international human rights group Helsinki Federation said Aug. 20 that Croat forces had looted and burned Serb houses throughout the Krajina. UN officials say dozens of Serb civilians have been killed and hundreds of homes burned during Croatia's re-taking of the Serb-held Krajina region earlier this month. The burning of Serb homes is seen as an attempt to ensure that the 150,000 Serbs who fled the Croatian offensive will not return, solidifying Croatia's new status as one of the most ethnically pure states in the Balkans. Monitor reporter looks at the sites In the first visit to Nova Kasaba by a Western reporter, what appeared to be a decomposed human leg was seen jutting from one of the alleged graves, and papers from inside the Srebrenica enclave and large, empty ammunition boxes were found nearby. US spy satellite photos reportedly show about 600 Muslim prisoners surrounded by guards in a nearby soccer field. Muslim women and children who passed the site while being bused to Bosnian government territory also reported seeing several hundred captured Muslims in the field. Satellite photos from a few days later show no trace of the captured men, but do show the new areas of fresh digging visited by a Monitor reporter. In televised interviews on Aug. 18, the new Bosnian Serb mayor of Srebrenica, Miroslav Deronic, said that Bosnian government soldiers killed during battles with Bosnian Serbs have been buried in mass graves, but the site in Nova Kasaba is not one of them. But US officials say the Monitor report confirms a massacre took place. ''If you look at the whole package [of evidence],'' a US official says, ''it all comes together.'' Bosnian Serb representatives and UN officials, in a rare moment of agreement, both say the Aug. 11 release of the US satellite photos of the alleged mass graves was an attempt to divert attention from Croat atrocities in the Krajina. ''I think they [the US] pass around this kind of alleged information to divert attention from what the Croats were doing,'' says Danielle Sremac, a spokeswoman for the Bosnian Serbs in Washington. ''The Croats are our buddies, and the Serbs are baby eaters. It's always been this way.'' Ms. Sremac said that the Central Intelligence Agency's assessment that the Bosnian Serbs had conducted the vast majority of war crimes in the conflict was leaked to divert attention during a June Bosnian government offensive to break the siege of Sarajevo. UN says US must have more UN officials say the US must have other evidence of alleged atrocities, but is not releasing it. ''We are writing stupid reports and talking to refugees,'' says the UN investigator. ''I'm sure they have answers to all these things. They release it for quite different purposes than people might think.'' US officials deny that they are selectively releasing information. ''We have limited intelligence assets for this kind of thing,'' says the US official. ''You can't blanket the whole country. We were lucky to have photos of the area before this happened.'' The UN is compiling a report of alleged atrocities committed following the fall of Srebrenica in July. But UN officials say their efforts are increasingly marginalized by the West's resolve to achieve peace at any cost.