ADDIS ABABA, Ethiopia (AP) — President Barack Obama urged Ethiopia's leaders Monday to curb crackdowns on press freedom and political openness as he began a visit that human rights groups say legitimizes an oppressive government.

"When all voices are being heard, when people know they are being included in the political process, that makes a country more successful," Obama said during a news conference with Ethiopian Prime Minister Hailemariam Desalegn.

Obama's trip marks the first visit by a sitting U.S. president to Ethiopia, a fast-growing economy once defined by poverty and famine.

Later Monday, Obama was to convene a meeting with African leaders on the crisis in South Sudan. The world's newest nation has been gripped by violence as warring factions in the government fight for power.

"The conditions on the ground are getting much, much worse," Obama said. He said if a peace agreement isn't reached by an Aug. 17 deadline, the U.S. and its partners would have to "consider what other tools we have."

Options under consideration include deepening economic sanctions and an arms embargo.

Obama arrived in Ethiopia late Sunday following a stop in Kenya, the country of his father's birth. The crisis in South Sudan and the human rights challenges on his agenda punctured a trip that had otherwise been a celebratory visit of the first black U.S. president to Africa.

Despite Ethiopia's progress, there are deep concerns about political freedoms on the heels of May elections in which the ruling party won every seat in parliament.

Obama said he was frank in his discussions with Ethiopian leaders about the need to allow political opponents to operate freely. He also defended his decision to travel to the East African nation, comparing it to U.S. engagement with China, another nation with a poor human rights record.

"Nobody questions our need to engage with large countries where we may have differences on these issues," he said. "That's true with Africa as well."

Ethiopia's prime minister defended his country's commitment to democracy.

"Our commitment to democracy is real — not skin deep," he said. Asked about his country's jailing of journalists, he said his country needed "ethical journalism" and reporters that don't work with terrorist organizations.

Ethiopia is the world's second-worst jailer of journalists in Africa, after Eritrea, according to the Committee to Protect Journalists.

Ahead of Obama's arrival, the Ethiopian government released several journalists and bloggers it had been holding since April 2014 on charges of incitement and terrorism. Many others remain in detention.

Sarah Margon, the Washington director of the organization Human Rights Watch, said Obama's visit undermines the president's goals of good governance on the African continent.

"In many ways, I guess it's a reward," Margon said. "Ethiopia at this time doesn't deserve that."

Despite differences on human rights, the U.S. sees Ethiopia as an important partner in fighting terrorism in the region, particularly the Somalia-based al-Shabab network. Ethiopia shares intelligence with the U.S. and sent troops into Somalia to address instability there.

The al-Qaida-linked al-Shabab claimed credit for a suicide bomb at a luxury hotel in Somalia's capital Sunday that killed nine people and injured nearly two dozen more. The Jazeera Hotel was considered the most secure in Mogadishu and is frequented by diplomats, foreigners and visiting heads of state.

Obama said the attack was a reminder that "we have more work to do" in stemming terrorism in the region.

Ethiopia has also been an important U.S. partner in the effort to end South Sudan's civil war. The prime minister was among the leaders joining Obama in Monday's meeting on the crisis.

South Sudan was thrown into conflict in December 2013 by a clash between forces loyal to former Vice President Riek Machar, an ethnic Nuer, and President Salva Kiir, a Dinka. The fighting has spurred a humanitarian crisis, throwing the country into turmoil four years after its inception.

The U.S. was instrumental in backing South Sudan's bid for independence, which was overwhelmingly supported by the country's people.