"We had proposed to both sides that if we could get to stabilization in eastern DRC, we could work on developing a spur from the Lobito Corridor up through eastern DRC," Phee told AFP in an interview ahead of her exit Monday as the Biden administration comes to an end.
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"We tried to offer positive incentives. A genuine framework -- fundamentally negotiated by the parties -- exists, and at the moment, Rwanda seems to have walked away," she said.
Rwanda-backed rebels known as the March 23 (M23) Movement since 2021 have seized swaths of eastern DRC, displacing thousands and triggering a humanitarian crisis.
Rwandan President Paul Kagame, while never admitting direct military involvement, has demanded the elimination of the Democratic Forces for the Liberation of Rwanda (FDLR), an armed group in DRC primarily composed of Hutu militants formed in the wake of the 1994 Rwandan genocide.
Authorities in Kinshasa accuse Rwanda of seizing valuable mines in the region amid the conflict.
Phee, who was part of the Biden administration's negotiations along with US intelligence chief Avril Haines, said the United States presented a solution that would include a DRC crackdown on the FDLR.
"They did not take that action," she said of Kinshasa.
"We put it all back together again and then I thought we were on a good track. And then in the end, President Kagame decided not to go to the Luanda summit in December, and you've seen Rwanda and M23 take more territory."
Kagame has dismissed recent peace initiatives such as the summit in the Angolan capital Luanda as little more than photo-ops that do not address "root causes."
- 'Heavy-handed' security response in Ethiopia -
Biden took office vowing to pay more attention to Africa than Donald Trump, his predecessor and successor, although the administration soon also became focused on the Ukraine and Gaza wars.
But one of the most devastating conflicts of this century was a two-year war in Ethiopia's Tigray region where at least 600,000 people died, according to an African Union envoy.The violence stopped with a ceasefire reached in November 2022 in the South African capital Pretoria.
"I'm very proud of the work we did to help end the war in Tigray, which at that time was the largest conflict in the world," Phee said.
But she voiced concern over Ethiopian forces' actions since then, in conflicts in the separate regions of Amhara and Oromia.
"It's a legitimate and difficult problem, as all insurgencies are, but we feel the security services are heavy-handed and are not as attentive to civilian casualties as they should be," she said.
The Biden administration booted Ethiopia out of a major trade pact in response to rights concerns in Tigray.
Phee said the United States "would like to be in a position to resume the kind of partnership that we had" but that Ethiopia still has steps to take.
- Still hopeful in Niger -
The United States also saw a setback when the military seized power in Niger in 2023 -- soon after a visit by Secretary of State Antony Blinken -- and moved closer to Russia.
The junta scrapped a military cooperation deal, forcing Washington to give up a $100 million drone base, soon after Phee voiced concern over Niger potentially selling uranium to Iran, whose nuclear program is under scrutiny.
In a diplomatic dustup, Nigerien authorities denied that there was a deal with Iran and called Phee's attitude "condescending."
Phee said her remarks to Niger should be understood more as an offer than warning.
She said she told Niger that "Iran is a bad actor in the world" and that a deal would cause problems due to sanctions on Tehran.
But she said she told them, "you deserve to use your uranium to benefit your people. We'll be happy to find you a reputable buyer."
"I'm hopeful that action on that kind of path will be taken by them."
