The relatives of three Bosnian Muslims killed 20 years ago in the Srebrenica massacre are taking their long-running legal battle against the Dutch government to the European Court of Human Rights.

The group is seeking criminal prosecution of three senior Dutch peacekeepers who were stationed in the U.N.-protected enclave at the time of the murders.

Dutch prosecutors in 2013 declined to bring charges against the three officers and a court upheld that decision on appeal in April.

Now a lawyer for the families, Liesbeth Zegveld, says she is taking the case to the rights court based in Strasbourg, France.

Zegveld alleges that the Dutch Defense Ministry "exerted undue pressure" on prosecutors not to file charges against the officers.

Defense Ministry spokesman Klaas Meijer on Sunday called that claim "totally unfounded."