Bosnia's Serb region said Monday it will file criminal charges against a U.S. envoy and international prosecutors in Bosnia over an investigation into government infrastructure deals.A spokesman for Serb Republic Prime Minister Milorad Dodik did not specify what the exact charges were but said they would be prepared this week.European and U.S. prosecutors working in Bosnia's state court under a 1995 peace agreement want documents on contracts for a lavish 110 million-euro ($138.5 million) government building in Banja Luka as well as a local highway, police sources and diplomats say.Dodik has repeatedly rejected handing over the documents, saying the state court did not have jurisdiction to probe his government's deals and accusing prosecutors and judges of bias against Serbs.He has accused U.S. diplomat Raffi Gregorian, the international Deputy High Representative in Bosnia, of plotting against his government along with the foreign prosecutors, judges and some journalists and civic activists."We suspect a criminal association that is aiming to stop a positive trend of development in Republika Srpska and show it in incorrect and negative light," Dodik said last week.His move to seek criminal charges could inflame tensions between the two halves of the country -- born out of a 1992-95 war involving Serbs, Muslims and Croats -- and some experts say fighting could break out again.Gregorian said Dodik seemed to be "losing touch with reality.""It's an obvious attempt to deflect attention from his repeated failure and broken promises regarding the legal obligation to turn over documents ... regarding a number of projects that have been carried out in the RS (Serb Republic) under questionable circumstances," Gregorian told Reuters. The leader of the Serb region that makes up Bosnia along with the Muslim-Croat federation, Dodik has pushed hard for greater autonomy for the Serb Republic since he came to power in 2006. Bosnia state court prosecutors are also probing deals with a Russian investor who acquired the Brod oil refinery and a joint venture with Czech power group CEZ, sources said.