Britain has issued a stern warning to Rwanda, cautioning that its alleged involvement in the escalating conflict in the Democratic Republic of Congo (DRC) could jeopardize over $1 billion in annual foreign aid.

Rwanda-backed M23 rebels seized control of Goma, a city of 2 million people in eastern DRC, on Monday, defying widespread international calls for a ceasefire. The rebels continued their advance on Wednesday, intensifying fears of further destabilization in the region.

According to the governments of Congo, the United States, and other Western powers, Rwandan forces have been supporting the M23 rebels in their operations in Goma. Rwanda, however, has denied any involvement in the conflict. Rwanda’s denial has prompted some commentators online to ask it join DRC in fighting M23 but no response so far has been made.

Speaking to Parliament on Tuesday, British Foreign Minister David Lammy emphasized that Rwanda receives over $1 billion in global aid annually, 0pp0pppp at risk if Rwanda continues to undermine the sovereignty of its neighbor.

“All of that is under threat when you attack your neighbors,” Lammy stated. “We in this House are clear that we cannot have countries challenging the territorial integrity of others. Just as we will not tolerate it on the European continent, we cannot tolerate it anywhere in the world.”

Lammy underscored the seriousness of the situation, noting that this week’s developments mark the most significant escalation of the long-standing conflict in eastern Congo since 2012. The roots of the hostilities trace back to the aftermath of Rwanda’s 1994 genocide, which spilled over into Congo, fueling ongoing violence and competition for control of the region’s vast mineral wealth.

“We have to be clear about that,” Lammy added, reaffirming the UK’s stance against violations of international borders.