Three former Defense Facilities Administration Agency officials pleaded guilty Monday to playing key roles in rigging bids in projects related to defense facilities.

In the opening session of their Tokyo District Court trial, Mamoru Ikezawa, 57, a former technical councilor at the facilities agency, apologized and said there is "no doubt" about the facts presented in the indictment.

The two others -- Takayoshi Kawano, 57, Ikezawa's successor in the post, and Takashige Matsuda, 53, a former facilities inspection officer in the agency's general affairs department -- also pleaded guilty.

The three former officials were accused of playing key roles in rigging bids for tenders for three air conditioning projects ordered by the agency between November 2004 and March 2005.

They conspired with employees of three manufacturers, including Taikisha Ltd., which formed consortiums and were awarded the contracts.

The projects included the installation of an air conditioning system in a Ground Self-Defense Force hospital in Tokyo and a system installed at a new agency facility, according to the indictment.

The three also played leading roles in rigging bids in five projects at the U.S. Marine Corps Air Station Iwakuni in Yamaguchi Prefecture, including one for relocating a runway, between January 2004 and March 2005, according to the indictment.

They were involved in bid-rigging of two quay construction projects at the U.S. Navy base in Sasebo, Nagasaki Prefecture, in March 2004.

Defense Facilities Administration Agency chief Iwao Kitahara said in a statement that his agency will try to regain public confidence by revealing the outcome of its internal probe into the matter.