WASHINGTON -- President Barack Obama said Monday that the U.S. is shifting its policy toward Sudan, offering the government incentives if it takes steps to improve the human suffering there and work toward internal peace.

But sanctions and pressure from the international community will follow if Sudan does not follow that path, Obama said.

The president said he will soon renew tough sanctions against the government of President Omar al-Bashir, whom the International Criminal Court has charged with crimes against humanity and war crimes for allegedly masterminding deadly attacks throughout Sudan's Darfur region.

"If the government of Sudan acts to improve the situation on the ground and to advance peace, there will be incentives. If it does not, then there will be increased pressure imposed by the United States and the international community," Obama said. "As the United States and our international partners meet our responsibility to act, the government of Sudan must meet its responsibilities to take concrete steps in a new direction."

Secretary of State Hillary Rodham Clinton announced details of the new approach at the State Department, which considers Sudan a "state sponsor of terrorism."

"Sitting on the sidelines is not an option," said Clinton, who was joined by U.N. Ambassador Susan Rice and Scott Gration, the president's special envoy to Sudan.

"It is up to us and our partners in the international community to make a concerted and sustained effort to help bring lasting peace and stability to Sudan and avoid more of the conflict that has produced a vast sea of human misery and squandered the potential and security of a vital region of the world."

The U.N. says the conflict in Darfur has claimed at least 300,000 lives as a result of violence, disease and displacement since February 2003, when ethnic African rebels took up arms against the Arab-dominated Sudanese government in Khartoum, claiming discrimination and neglect. Some 2.7 million fled their homes. At its peak in 2003-2005, the situation was called the world's worst humanitarian crisis.

Obama has labeled the conflict in Darfur as genocide.

Asked to justify how Obama can work more closely with someone he believes is guilty of genocide, White House press secretary Robert Gibbs said: "The president still believes that. But what we're trying to do is seek a comprehensive solution to this problem that again addresses both the humanitarian crisis that has happened and is ongoing in Darfur, as well as a comprehensive peace between the North and South."

Obama said the U.S. and the international community must act "with a sense of urgency and purpose," a sentiment that was underscored when Darfur peacekeepers reported a sizable and unusual increase in military activity by Sudanese government forces and a Darfur rebel group in northern Darfur.

The United Nations-African Union Mission in Darfur expressed grave concern about the build up "as it may signal the impending start of a new cycle of armed confrontations in the area." Mission spokesman Kemal Saiki said peacekeepers in the area have seen a buildup of military material and personnel as well as digging of trenches by government forces and rebels from the Sudan Liberation Army-Abdul Wahid faction.

In Khartoum, Ghazi Salah Eddin Atabani, a senior adviser to al-Bashir and the government's point man on Darfur, appeared on Sudanese TV and contrasted the new U.S. policy with its more "extremist" past.

"We hope that this will end the debate among U.S. officials and we hope that now they will think with one mind and speak with one tongue," he said.

Rice and Gration have clashed over how far to engage al-Bashir. Gration publicly has argued for a less strict line toward al-Bashir, whom he has told officials is the key to resolving the situations in Darfur and in southern Sudan, which in 2005 signed a provisional peace deal with the government in Khartoum, ending Africa's longest-running civil war. Rice favored taking a harder line approach.

The new policy is designed to bring Khartoum into the fold by offering incentives for improvements in the situation in Darfur and in southern Sudan, which is scheduled in 2011 to hold a referendum on succession, they said.