GOMA, Congo (AP) — More than 400 civilians have been killed since the Rwanda-backed M23 armed group escalated its offensive in eastern Congo, officials said. M23’s latest offensive comes despite a U.S.-mediated peace agreement signed last week by the Congolese and Rwandan presidents in Washington. The accord didn’t include the rebel group, which is negotiating separately with Congo and agreed earlier this year to a ceasefire that both sides accuse the other of violating. However, it obliges Rwanda to halt support for armed groups. The conflict has displaced over 200,000 people since early December. The situation has created a significant humanitarian crisis, with fears of the conflict spilling into neighboring Burundi.