The mastermind behind a secret chemical and biological warfare program said Friday that Western countries, including the United States, swapped sensitive military information with apartheid South Africa.

Dr. Wouter Basson, whose scientists made poisons for government assassins and researched a bacteria to kill only black people, told a commission investigating apartheid-era abuses that Western governments gave him helpful information as he sought to set up the program in the early 1980s.Basson gave no details of what secrets were passed, but he described attending a 1981 conference in San Antonio, Texas, with army officers from the United States, West Germany, Japan, Britain and Canada.

Hanif Vally, a lawyer for the Truth and Reconciliation Commission, asked Basson if during the conference U.S. officials had told him about their own chemical and biological warfare programs in an "incredible amount of detail."

"That is correct," replied Basson.

During the Cold War, Western government officials and army officers were especially open because they wanted details on the chemical warfare capability of Soviet-backed countries neighboring South Africa, Basson said.

"That was why I had good access to senior government officials and people at that time," he said.

With the Truth Commission's mandate expiring Friday, Basson's testimony came at the last possible moment and follows two days of legal wrangling to delay proceedings.