Pope Benedict XVI has made an emphatic appeal to Africans to rid the continent of corruption once and for all.
The 81-year-old was speaking during a televised address in Angola during a week-long tour of African countries.
The Pope said that with integrity, magnanimity and compassion Africans could transform their continent.
Former UN Secretary General Kofi Annan has launched a similar attack, accusing many African presidents of running anti-democratic regimes.
The Pope arrived in the Angolan capital Luanda on Friday from Cameroon, on the second leg of his African tour.
The BBC's Louise Redvers, in Luanda, said thousands of people gathered at the city's airport to greet him, some waiting from the early hours.
Among the crowds many women in traditional Catholic uniforms of brightly coloured headscarves and sarongs.
The crowd began to cheer as the papal plane flew overhead but broke into a frenzy as his motorcade drove into the city, with some people breaking free at the sides of the roads to run alongside his car, our correspondent says.
The Pope said in his address that the people in Angola knew "the time of hope has arrived" for Africa and that every "decent, hopeful human behaviour" would make a difference to God and in history.
"My beloved friends, with an upright, magnanimous heart that is also compassionate, you can transform this continent, freeing the people from the whip of greed, violence, disorder and guiding it through the path of those principles that are indispensible to any modern democracy," he said.
Those principles, he said, included respect, transparent governance, freedom of the press, health care and adequate schooling as well as the promotion of human rights.
The 81-year-old pontiff said Africans needed "a firm determination to change hearts and finally put a stop, once and for all, to corruption".
He also repeated concerns raised while he was in Cameroon that modern culture was destroying traditional African family values and he criticised the spread of sexual violence and abortion.
The Pope's speech was echoed by President Jose Eduardo dos Santos, who has been Angola's leader for the past three decades and through a civil war which has left hundreds of thousands dead.
Mr dos Santos said Angolans were "looking for the best ways to rebuild what was destroyed in the recent past, and to build a modern society that will integrate all the people without discrimination or exclusion".
Mr Annan said the Kenyan people were watching their leaders closely
The Pope's comments came on the same day as Mr Annan, on a visit to Nigeria, launched a strong attack on some African leaders.
He said that it was a matter of profound shame that once elected, many African leaders come to believe that only they can be trusted to run their countries.
He accused such leaders of governing for the benefit of a ruling elite, rather than society as a whole and said that in too many African countries, human rights and the rule of law were disregarded.
Mr Annan is due to attend talks with Kenya's leaders in Geneva next week to assess the fragile power-sharing agreement which followed last year's post-election violence.
Mr Annan told Kenya's leaders their people had been shocked by the events of 2008 and were now demanding more from their politicians.
The BBC's Karen Allen says the meeting is intended to be about what lessons have been learned, but in reality it is likely to be tougher on the leaders.
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