Congressional investigators say they have uncovered evidence that U.S. companies sold bacteria and an advanced computer for missile tests to an Iraqi institution specializing in nuclear and germ warfare research.

A House subcommittee has obtained information that bacteria were sold to Iraq as well as many other sensitive technologies that could be used to build unconventional weapons, the committee's chief counsel, Ted Jacobs, said yesterday.

"We have obtained information on sales of bacteria to Iraq. We don't yet know what they were intended for, and we are finding it a struggle to get more information from the Commerce Department," Jacobs said.

According to a government source, the so-called biotoxins were exported under Commerce Department license to Saad 16, a giant military research complex for nuclear and chemical weapons and ballistic missiles in Mosul in northern Iraq.

The source said a hybrid digital-analog computer, used to support wind tunnel tests for ballistic missiles, was also sold to the same institute in 1987 over the objections of the Defense Department.

The Pentagon thought it had blocked the sale but recently discovered that the computer was operating in Iraq. The Commerce Department had lost all the documentation relating to the sale, the source said. A Commerce Department spokeswoman declined to comment on this case or others relating to exports to Iraq.

Subcommittee Chairman Rep. Doug Barnard Jr. (D-Ga.) wrote to Commerce Secretary Robert A. Mosbacher Oct. 16 asking him to release to the public information about the sales of sensitive technology to Iraq. In a responding letter, Undersecretary for Export Administration Dennis Kloske said disclosure of such information was against the national interest.

Barnard said: "It is unfortunately true that the United States and our allies have, over the past decade, supplied {Iraqi President} Saddam Hussein and Iraq with some of the tools of war which he may now use against American soldiers."