The stadium in Cameroon capital Yaounde was the Pope's first open-air mass of his visit to Africa
Some 60,000 people have packed a football stadium in Cameroon's capital to hear Pope Benedict XVI celebrate his first open-air Mass in Africa.
The pontiff, on a week-long visit to the continent, arrived at the arena in a bullet-proof, open-topped vehicle.
He said the extended African family was under threat from urbanisation and warned against creeping materialism.
The Pope has been criticised on his tour for remarks refusing to advocate condoms as a way to help stop HIV/Aids.
Earlier on Thursday, the Pope met leaders of Cameroon's Muslim community.
The 81-year-old - who travels to Angola on Friday - said peaceful co-existence between Muslims and Christians in Cameroon should be seen as a "beacon to other African nations".
In his address at the Amadou Ahidjo national stadium, the Pope said Africa was "a continent of hope" but it was at risk from those seeking to "impose the tyranny of materialism".
Thousands were left outside when the Mass began as the arena was full
The pontiff said Africa, especially Cameroon, had to treasure the preciousness and dignity of human life.
The BBC's Caroline Duffield, who attended the stadium service in the capital Yaounde, says some will take that remark as a quiet rebuke to Cameroon's government over human rights, but for some people it was not enough.
Our correspondent says the Pope received a passionate display of support from the worshippers, many of whom were young.
She adds the arena is on a hill above Yaounde and tens of thousands had climbed up in the morning heat to hear him speak.
Some said they had queued outside the stadium all night to be sure of getting in.
Many of those who attended the event wore T-shirts and other items of clothing with the Pope's picture.
Marshalls struggled to contain the rush for the best seats when the gates were opened and thousands were left outside when the Mass began.
On his way to Cameroon, the Pope said HIV/Aids was "a tragedy that cannot be overcome by money alone, that cannot be overcome through the distribution of condoms, which can even increase the problem".
The Vatican has sought to play down the controversy over the remarks, saying he had merely been expressing the Catholic Church's policy.
But France, Holland and even the Pope's native Germany expressed concern.
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