The Brazilian Congress, after the most thorough probe yet of the country's nuclear programs, says it has established that the nation's former military rulers intended to build an atomic bomb.

"At an historic moment there was a decision, taken within the Planalto palace - the seat of government - to build a nuclear artifact," a congressional committee of inquiry said in its conclusions made public Friday.The military ruled Brazil from 1964 to 1985. Legislators said it was under the last of the five military presidents, Gen. Joao Figueiredo, that the government decided to make a nuclear bomb.

The congressional panel, formally known as the Committee of Parliamentary Inquiry into the Nuclear Program, issued its conclusions after a five-month probe.

The 20-member congressional committee has so far given only the conclusions of its report, but the full text, due to be published shortly, is expected to contain more details of Brazil's nuclear activities.

The current civilian administration of President Fernando Collor de Mello has pledged not to make nuclear weapons.

Brazil has developed uranium enrichment technology and scientists say it could make a bomb if it so wished.

Collor told Brazilian journalists in New York in September that the military had had a project called Operation Solimoes to build a bomb, but he provided only scanty details.

One of the committee's conclusions was that a 1,050-foot-deep shaft in the Amazon, built in the early 1980s, had been constructed with the express purpose of testing nuclear weapons.

No such test was ever carried out, and on Sept. 18 Collor flew to the Cachimbo air base to throw lime down the shaft and declare it closed. Last month the congressional committee traveled to Cachimbo and confirmed that the hole had indeed been filled in.

The committee questioned many key people in Brazil's nuclear program, including Figueiredo.