The head of the Catholic Church in Mozambique has told the BBC he believes some European-made condoms are infected with HIV deliberately.
Maputo Archbishop Francisco Chimoio claimed some anti-retroviral drugs were also infected "in order to finish quickly the African people".
The Catholic Church formally opposes any use of condoms, advising fidelity within marriage or sexual abstinence.
Aids activists have been angered by the remarks, one calling them "nonsense".
"We've been using condoms for years now, and we still find them safe," prominent Mozambican Aids activist Marcella Mahanjane told the BBC.
The UN says anti-retrovirals (ARVs) have proved very effective for treating people with Aids. The drugs are not a cure, but attack the virus on several fronts at once.
The BBC's Jose Tembe in the capital, Maputo, says it is estimated that 16.2% of Mozambique's 19m inhabitants are HIV positive.
About 500 people are infected every day.
Archbishop Chimoio told our reporter that abstention, not condoms, was the best way to fight HIV/Aids.
"Condoms are not sure because I know that there are two countries in Europe, they are making condoms with the virus on purpose," he alleged, refusing to name the countries.
"They want to finish with the African people. This is the programme. They want to colonise until up to now. If we are not careful we will finish in one century's time."
Aids activists in the country have been shocked by the archbishop's comments.
"Condoms are one of the best ways of getting protection against catching Aids," said Gabe Judas, who runs Tchivirika (Hard Work) - an theatre group that promotes HIV/Aids awareness.
"People must use condoms as it's a safe way of having sex without catching Aids," he told the BBC.
Archbishop Chimoio, who made the remarks at celebrations to mark 43 years of independence, said that fighting the disease was a serious matter.
"If we are joking with this sickness we will be finished as soon as possible.
"If we want to change the situation to face HIV/Aids it's necessary to have a new mentality, if we don't change mentality we'll be finished quickly," he said.
"It means marriage, people being faithful to their wives... (and) young people must be abstaining from sexual relations."
Our correspondent says the archbishop is well respected in the country and the Catholic Church played a leading role in sponsoring the 1992 peace deal that ended a 16-year civil war.
Some 17.5% of Mozambicans are Catholic.