ADDIS ABABA, Ethiopia -- President Obama will convene a meeting Monday with the leaders of several African nations and the chairwoman of the African Union, senior administration officials said Sunday, to determine whether there is sufficient regional support for sanctions if the ongoing peace process in South Sudan breaks down.

The conflict in South Sudan, a brutal civil war that has divided a country created just four years ago, has become a major humanitarian crisis that threatens to destabilize the region. It has evolved into a quasi proxy war between Uganda, which backs the current government of President Salva Kiir, and Sudan, which is arming the rebels.

The presidents of Kenya and Uganda will attend the 90-minute session, officials said, along with the prime minister of Ethiopia, the chairwoman of A.U. and the Sudanese foreign minister. The meeting will also cover other topics such as combating terrorism and violent extremism in East Africa.

“We have a huge assistance relationship with South Sudan, and we have a history with South Sudan,” deputy national security adviser Ben Rhodes told reporters Sunday. “And what I think we’re going to be focused on is how can we not impose a solution from the United States but work with some of the other countries in the region who share our concerns -- Uganda, Ethiopia, Kenya -- to try to find a way out of this impasse that is not going to be anything but more humanitarian suffering for the people of South Sudan.”

The U.S. is also looking at how to bolster counterterrorism efforts in East Africa, as Islamist militants have continued to strike at civilian targets. On Sunday, a bomb blast killed at least 10 people at the Jazeera Palace Hotel in the Somali capital of Mogadishu; the terrorist group al-Shabab claimed credit for the attack.

In a statement, National Security Council spokesman Ned Price said, "This attack is yet another reminder of the unconscionable atrocities that terrorist groups continue to perpetrate against the people of Somalia."

"As the president underscored during his meetings with Kenyan President Kenyatta over the last two days—and as he will reiterate during his visit to Ethiopia and the African Union, two staunch supporters of the Federal Government of Somalia and the Somali people—the United States remains steadfast in our commitment to work with Somali authorities, our regional partners, and the broader international community to bring an end to acts of terrorism and combat violent extremism in Somalia," Price added.

African nations, led by Ethiopia, have been trying to broker a peace in South Sudan through the Intergovernmental Authority on Development (IGAD), a regional body, and are almost ready to present a possible compromise to the warring parties. The two sides will have until Aug. 17 to response to the proposal, and White House officials said they need to be prepared to exert significant pressure on them should they reject the offer.

Administration officials painted a pessimistic portrait of the warring factions, saying they had little reason to believe they would accept any sort of peace deal at this point despite the tremendous human toll their dispute has wrought. Forty percent of South Sudanese receive humanitarian assistance, and much of it comes from the United States.

An administration official, who asked for anonymity because of the sensitive nature of the talks, said a positive outcome is not a “likelihood.” In that case, the official said, the United States would explore other options, which could include setting up a transitional government and then calling an election; the application of increased pressure on both sides through new sanctions; or an arms embargo.

“I don’t think anybody should have high expectations that this is going to yield a breakthrough," the official said. "The parties have shown themselves to be utterly indifferent to their country and their people, and that is a hard thing to rectify.”

Speaking to reporters last week, White House national security adviser Susan E. Rice said she was “deeply disappointed” that the world’s newest country had devolved into chaos over the past year and a half.

“Thus far, the sides have put their own personal power and wealth ahead of the interests of their people and have refused to accept numerous rational proposals for a peaceful resolution of the conflict,” Rice said.

Neither South Sudanese government officials nor the rebels will be invited to the talks, officials said. “, I think at this point our view is that both parties are part of the problem and this is not an opportunity for them to have a bunch of air time,” said the administration official who asked for anonymity.

Princeton Lyman, a senior adviser to the U.S. Institute for Peace who served as  the U.S. special envoy for Sudan and South Sudan from 2011 to 2013, said the fact that both Uganda and Sudan are directly involved in the conflict “makes it difficult . . . to really put pressure on the parties in South Sudan.”

He noted that U.S. officials and others “have talked and talked and talked about imposing an arms embargo, but they’ve never reached that point, and if the Africans don’t agree on an arms embargo the [U.N.] Security Council won’t agree on an arms embargo.”

On Sunday, the administration official said possible sanctions could include those targeting the assets and travel of individuals; U.S. sanctions; or international sanctions.