Rwandan President Paul Kagame and DR Congo President Felix Tshisekedi each offered commitments to Haines to "de-escalate tensions in eastern DRC," a White House statement said.
"Acknowledging the long history of conflict in this region, Presidents Kagame and Tshisekedi plan to take specific steps to reduce current tensions by addressing the respective security concerns of both countries," it said.
The White House did not immediately go into specifics on their promises but said it drew on previous African-led negotiations in the Kenyan capital Nairobi and a follow-up conference in the Angolan capital Luanda.
The Angolan initiative, exactly a year ago, called for a ceasefire and disarmament of rebel groups in the eastern DRC including M23 rebels with a potential regional force to enforce compliance.
Despite that agreement, M23 rebels have stepped up attacks in recent months and have seized much of North Kivu province.
Kinshasa accuses the M23 rebels, who are primarily Tutsis, of enjoying support from Rwanda -- a claim publicly backed by the United States.
Kagame frequently has demanded action against Rwandan Hutus in the neighboring country linked to the 1994 genocide against Tutsis.
Earlier this month, M23 rebels seized the North Kivu village of Kishishe, around the historic stronghold of the Democratic Forces for the Liberation of Rwanda, created by Rwandan Hutu leaders linked to the genocide.
In November 2022, M23 rebels killed 171 people in Kishishe, according to the UN, mainly boys and men they accused of being militiamen.
The United States, which has cordial relations with both countries, has repeatedly sought to mediate, with Secretary of State Antony Blinken recently calling both Kagame and Tshisekedi.
The trip by Haines, who was accompanied by top US officials on Africa, comes as international powers try to encourage calm in the runup to presidential elections in DR Congo on December 20.
The country has endured decades of instability but experienced its first peaceful transfer of power after Tshisekedi's victory following the last presidential election in December 2018.
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