ADDIS ABABA (AFP) ― The African Union’s new chairman faced tough challenges Sunday as U.N. chief Ban Ki-moon warned that a furious row between Sudan and South Sudan threatened regional security.

Thomas Boni Yayi, the president of Benin, vowed to work for peace in his one-year tenure as the 54-member bloc’s rotating head, as sideline talks at the two-day summit tried to tackle several hotspots across the continent.

Top of these were Sudan tensions. Ban said both Sudanese President Omar al-Bashir and his South Sudan counterpart Salva Kiir lacked the “political will” to tackle border and oil disputes since the South seceded last July.

“The situation in Sudan and South Sudan has reached a critical point, it has become a major threat to peace and security across the region,” Ban told reporters on the sidelines of the summit.

Khartoum and Juba are at loggerheads over pipeline transit fees to transport the South’s oil to port in the rump state of Sudan.

Tensions have also risen over the two countries’ still undemarcated border

― cutting through oil fields ― as well as allegations by each side that the other backs proxy rebel forces against the other.

“The international community needs to act, and it needs to act now,” Ban added. “As long as these issues remain unresolved, tensions will only grow.”

War-torn Somalia, violence in Nigeria and riots in Senegal following an octogenarian president’s resolve to cling to power, are also expected to be addressed in sideline talks in meetings in the Ethiopian capital.

Boni Yayi, who succeeded Equatorial Guinea’s President Teodoro Obiang Nguema as AU chairman, said he wanted to “ensure that peace comes back our continent” as he accepted the post.

“We shall continue to work hand in hand to ensure that we consolidate all what we have achieved so far,” said Boni Yayi, an economist who is not expected to rock the boat in his new post, a largely ceremonial position.

“The development of our continent is in our hands my dear presidents ... it is in unity and cohesion that our continent will ensure its development,” Boni Yayi added, urging peace in Sudan and South Sudan, the Sahel region and in Nigeria.

However, leaders were also focused on the race for the bloc’s most influential post, the head of the bloc’s executive arm, the AU Commission.

While the AU chairmanship rotates among African leaders and is held for one year, intense lobbying continues ahead of a vote Monday to be commission chief.

On Monday, the 18th ordinary summit will chose in a secret ballot whether South Africa’s Home Affairs Minister Nkosazana Dlamini-Zuma will take over from incumbent Jean Ping. No woman has held the AU Commission post.

South Africa said Saturday it was optimistic Dlamini-Zuma, former wife of President Jacob Zuma, can unseat Gabon’s Ping, who was first elected in 2008.

Sources close to Ping say he is confident of re-election, counting on support from French-speaking West and Central Africa countries.

AU leaders, who gathered in their sleek new headquarters ― a $200m high-rise center built and donated by the Chinese government ― were meeting for their first summit since the death of the bloc’s founder Moammar Gadhafi.

After a year that saw the AU faced with a post-election crisis in Ivory Coast as well as the Arab Spring revolutions, Obiang summed up his stint by accusing “external powers” of trying to “perpetuate their influence” in Africa.

“Africa should not remain indifferent to external interference. Africa should not be questioned with regards to democracy, human rights, governance and transparency in public administration,” he said.

Ban said the Arab Spring was “a reminder that leaders must listen to their people.”

“Events proved that repression is a dead end. Police power is no match to people power seeking dignity and justice,” he said, also urging that African leaders must also respect gay rights.

Homosexuality is illegal in most African countries.

“One form of discrimination ignored or even sanctioned by many states for too long has been discrimination based on sexual orientation or gender identity,” Ban said.

Previous external criticism of restrictions imposed on homosexuals has attracted angry responses from African leaders, who claim it is alien to their culture.