"The cycle of attacks and escalation is reckless, it is destructive and it must be ended," Mr. Bush said ahead of his Africa trip next month. "We must build peace at the heart of Africa."
He charged that the "freedom and dignity of a nation is under assault" in Zimbabwe, facing its worst economic and political crisis since independence in 1980. President Robert Mugabe won last year's elections, which independent observers say were marred by state-orchestrated political violence, intimidation and vote rigging.
"I urge all nations, including the nations of Africa, to encourage a return to democracy in Zimbabwe," Mr. Bush said.
He also announced $100 million in new U.S. aid to combat terrorism at the continent's airports and seaports.
In a speech to a group representing American investors in Africa, Mr. Bush urged the establishment by June 30 of a transitional government in Congo, and asked leaders of neighboring governments to actively support the creation of an integrated national army. Congo's nearly 5-year-old war has killed 3.3 million people, most through war-induced famine and disease, according to aid groups.
Mr. Bush also emphasized the importance of achieving a peace agreement in Sudan, where civil war broke out 20 years ago and has claimed more than 2 million lives. "The north and south must finalize a just and comprehensive peace agreement," Mr. Bush said.
He said he would return his special envoy, John Danforth to Sudan in two weeks. "He will make clear the only option on the table is peace," Mr. Bush said. "Both sides must now make their final commitment to peace and human rights and end the suffering Sudan."
Mr. Bush chose to speak out on some of the bloodiest, longest conflicts in Africa in advance of his five-day trip starting July 7.
In the hours before his address, angry crowds laid out bloody, broken bodies of shelling victims at the gates of the U.S. Embassy in Monrovia, Liberia, accusing U.S. Marines and the United States government of failing to protect trapped people from fighting that has overrun the city.
Taylor renounced his pledge to cede power Friday under a new peace accord, a move that sparked new violence in Liberia's 3-year civil war. Just days after the deal got under way with a fragile cease-fire, Taylor, a former warlord indicted for war crimes, said he intended to serve out the six months remaining in his term and perhaps run for re-election.
"President Taylor needs to step down," Mr. Bush said to applause from the crowd, "so that his country can be spared further bloodshed."
Mr. Bush gave no hint he intended to offer U.S. military assistance in any of the countries, as some outsiders have pleaded for.
He announced a new $100 million initiative to increase security at airports and seaports in Kenya, Ethiopia, Djibouti, Uganda and Tanzania. "We will give them the tools and resources to win the war on terror," Mr. Bush said.
Mr. Bush offered a lengthy overview of administration efforts to combat AIDS and hunger in Africa, the centerpiece a new law authorizing a tripling of U.S. funds for fighting AIDS in 12 African and two Caribbean countries. "My message today, and my message when I go to the continent, is you are not alone in the fight," Mr. Bush said. The five-year, $15 billion program still needs congressional approval, and Mr. Bush asked for lawmakers' support.
For the second time in a week the president also accused Europe, without singling out any nations, of worsening hunger in Africa by closing its markets to genetically modified the food.
"The ban of these countries is unfounded, it is unscientific, it is undermining the agricultural future of Africa, and I urge them to stop this ban," Mr. Bush said.
Mr. Bush travels starting July 7 to Senegal, South Africa, Botswana, Uganda and Nigeria. It is a less ambitious trip than he had planned for January, before postponing it because of the looming Iraq war. And it is far smaller in scale than the trip some of his advisers at the National Security Council had urged Mr. Bush to undertake. Stops in Kenya and Mauritius were dropped.