A Cambodian judge on a U.N.-backed war crimes tribunal trying Khmer Rouge leaders is denying accusations that he failed to thoroughly investigate two cases submitted by prosecutors.

In a statement released Wednesday, You Bunleng says he and a former German co-investigating judge performed witness interviews and crime-site visits while investigating cases 003 and 004.

The joint U.N.-Cambodian tribunal was established in 2006 to try suspected war crimes perpetrated during Khmer Rouge rule in Cambodia in the late 1970s.

Rights groups have accused the tribunal's two co-investigating judges of closing their probe of Case 003 in April without interviewing key witnesses or visiting suspected crime scenes. They also have accused the judges of failing to thoroughly investigate Case 004.

Critics say the two judges were influenced by pressure from the Cambodian government not to pursue more Khmer Rouge cases beyond the two that have already come to trial. The government has said such cases risk undermining the country's stability.

German judge Siegfried Blunk resigned from the tribunal last week, complaining about interference by the Cambodian government.

You Bunleng says he was very surprised by Blunk's resignation. The Cambodian judge says he and Blunk had carried out investigative activities “independently, without any obstacle.” You Bunleng also pledged to “resist any attempt to interfere in his works from any source.”