President Bush stepped deeper into Africa's political and military strife Thursday, calling for Liberian President Charles Taylor (search) to give up power, for an interim government to be installed in Congo (search) by next week and for democracy to be established in Zimbabwe (search).

"The cycle of attacks and escalation is reckless, it is destructive and it must be ended," Bush said ahead of his Africa trip next month. "To encourage progress across all of Africa, we must build peace at the heart of Africa."

Bush charged that the "freedom and dignity of a nation is under assault" in Zimbabwe, which is facing its worst economic and political crisis since independence in 1980. President Robert Mugabe (search) won last year's elections. Independent observers and the Bush administration say those elections 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," Bush said.

In an impassioned speech to a group representing American investors in Africa, Bush urged leaders of neighboring governments to actively back the establishment of a transitional government in Congo by Monday. Bush's deadline seemed ambitious: Talks are under way on forming an interim government, but there has been no sign of an imminent breakthrough.

Bush also appealed to Congo's neighbors to back 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.

Bush also emphasized the importance of achieving a peace agreement in Sudan (search), 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," Bush said.

He said he would return his special envoy, former Sen. John Danforth, to Sudan in two weeks. "He will make clear the only option on the table is peace," Bush said. "Both sides must now make their final commitment to peace and human rights and end the suffering in Sudan."

Bush chose to speak out on some of the bloodiest, longest conflicts in Africa in advance of his five-day trip there starting July 7.

In the hours before his address, angry crowds laid out the broken corpses of shelling victims at the gates of the U.S. embassy in Monrovia (search), Liberia, accusing American Marines and the U.S. government of failing to protect trapped people from fighting that has overrun the city.

On Friday, Taylor renounced his pledge to cede power under a new peace accord, a move that sparked new violence in Liberia's three-year civil war.

"President Taylor needs to step down," Bush said to applause from the crowd, "so that his country can be spared further bloodshed."

It was an extraordinary demand by the American government for a democratically elected leader of another country to step down. Taylor was elected in 1996 in a free and open presidential election.

The call for Taylor's resignation was also remarkable because Bush spent part of his speech expressing his hope that such democracy would take root in Africa. "Introducing democracy is hard in any society," he said.

Bush gave no hint he intended to offer U.S. military assistance in any of the countries he mentioned Thursday, as some outsiders have pleaded for.

He announced a new $100 million, 15-month initiative to bolster anti-terror efforts in Kenya, Ethiopia, Djibouti, Uganda and Tanzania. It will aim to step up patrols at airports and seaports, increase intelligence-sharing and improve computer databases to track terrorists.

"Many African governments have the will to fight the war on terror, and we are thankful for that. We will give them the tools and resources to win the war on terror," he said.

Bush's trip to Africa includes stops in 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. The trip Bush plans for next month also brings him to far fewer stops than the one some aides at the National Security Council were urging him to make this time.

"America is committed to the success of Africa, because we recognize a moral duty to bring hope where there's despair," Bush said. Moreover, he said, "failed states spread instability and terror that threatens us all."

Also Thursday, Bush met with Mauritian Prime Minister Anerood Juganauth. Bush was supposed to visit Mauritius on a trip to Africa that originally was scheduled for January. Bush promised to visit the tiny island off Africa's eastern coast another time, Juganauth told reporters after the meeting.