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AMSTERDAM, June 1 (Reuters) - Families of the victims of the 1995 Srebrenica massacre in Bosnia will sue the Dutch state and the United Nations, which they blame in part for allowing the killings to happen, lawyers said on Friday. The law firm representing a group of about 6,000 family members said it would file a civil suit in the Netherlands on Monday.

During the 1992-95 Bosnian war, Srebrenica became a supposed safe area guarded by a Dutch army unit operating under a United Nations mandate.

The lightly armed Dutch soldiers, lacking air support, were forced to abandon the enclave to Bosnian Serb forces, who took away and massacred some 8,000 Muslim men and boys relying on the protection of the Dutch troops.

The Dutch government led by Wim Kok resigned in 2002 after a report on the massacre blamed politicians for sending the Dutch U.N. troops on an impossible mission.

"In the past three years, a strong case has been built against the Dutch state and the United Nations, who are held to be partially responsible for the fall of the enclave and the genocide that followed," law firm Van Diepen Van der Kroef said in a statement.

"The case must lead to the surviving relatives of this drama finally receiving recognition and redress."

A spokesman for the office of Dutch Prime Minister Jan Peter Balkenende said the Dutch state would not respond until it had received the legal documents.

"The cabinet has said several times that it sympathises with the surviving relatives of Srebrenica," he said.

A spokeswoman for the United Nations said: "We have no reaction yet. We are aware of it and certainly this is going to be followed very closely..."

"We are waiting for this to be introduced into a court." (Additional reporting by U.N. bureau)

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