Addis Ababa, Ethiopia (AFP)–United Nations (UN)  chief Antonio Guterres on Saturday demanded the Democratic Republic of Congo’s “territorial integrity” be respected and a regional war avoided, at an African summit the day after Rwandan-backed fighters seized a second DRC provincial capital.

With international pressure mounting on Rwanda to curb the fighting in eastern DR Congo (DRC), the conflict was set to dominate the African Union summit as it opened in Addis Ababa.

Rwanda’s President Paul Kagame was seen attending meetings at the gathering, but DR Congo’s president Felix Tshisekedi was absent from the summit as the M23 advanced through his country’s territory.

Having routed the Congolese army to capture the key provincial capital of Goma in North Kivu last month, the Rwandan-backed armed group pushed into neighbouring South Kivu.

It took a key airport there before marching virtually unchecked into another key city, Bukavu, on Friday, security and humanitarian sources said.

“The fighting that is raging in South Kivu — as a result of the continuation of the M23 offensive — threatens to push the entire region over the precipice,” Guterres told leaders in an address to the summit, without mentioning Rwanda.

He urged dialogue, saying that a regional escalation must be avoided “at all costs”, and that there was “no military solution”.

“And the sovereignty and territorial integrity of the DRC must be respected.”

-DRC ceasefire call –

With the spectre of a regional conflagration in eastern DRC, the AU has been criticised for its timid approach and observers have demanded more decisive action.

The European Union on Saturday said that it was “urgently” considering all options following the news from Bukavu.

“The ongoing violation of the DRC’s territorial integrity will not go unanswered,” it warned.

Guterres stressed in a later press conference however: “The key to the solution of the problem is here” in Africa.

East and southern African leaders on February 8 called for an “immediate and unconditional” ceasefire within five days, but fresh fighting erupted on Tuesday.

A meeting of the AU’s Peace and Security Council dedicated to the conflict ran late into the evening on Friday, with neither Kagame nor Tshisekedi attending.

A government source told AFP that Tshisekedi would not attend the summit over the weekend either as he had to “closely follow the situation on the ground in DRC”.

AFP journalists in Bukavu reported sporadic gunfire on Saturday, with the streets deserted as residents sheltered inside after reports of overnight looting.

Across the nearby border in Rwanda, AFP reporters in the town of Rusizi said the streets were unusually calm but some gunshots could be heard.

Tshisekedi, speaking at the Munich Security Conference on Friday, urged nations to “blacklist” Rwanda, condemning Kigali’s “expansionist ambitions”.

Rwanda has not admitted backing M23 but has accused extremist Hutu groups in DR Congo of threatening its security.

DR Congo accuses Rwanda of plundering valuable minerals in its eastern provinces.

Neighbouring Burundi has also sent thousands of troops to support DR Congo’s struggling army.