The main power lines to the city of Goma in eastern Democratic Republic of Congo have been cut due to an escalation in rebel fighting nearby, leaving hospitals and water systems without power, the electricity network operator said on Tuesday.

Virunga National Park, which operates the network that supplies about 80% of Goma’s electricity, said on Monday that clashes between Congo’s army and the M23 rebels had severed the main power lines to Goma, a city of over 2 million people and the capital of North Kivu province.

The M23 is a Tutsi-led armed group that Congo and U.N. experts say is supported by neighbouring Rwanda. Rwanda denies this.

A spokesperson for the park said on Tuesday that engineers had managed to access the site to begin repairing the main line, but that bombing continued around them.

Clashes with the M23 rebels have moved closer to Goma in recent weeks, causing the U.N. peacekeeping mission MONUSCO and the Congolese army to launch a new operation to reinforce its security perimeter, the United Nations said last Friday.

The latest fighting has forced around 300,000 people to flee their homes, bringing to about 1 million the number of people displaced by the M23 conflict to date, the U.N. estimates.

On the outskirts of Goma are huge camps for displaced persons that get their clean water from pumping stations which cannot function without electricity, Virunga National Park said.

“When there is a power cut like this, it is a crime against humanity. There are hospitals and pumping stations in the city that use this power,” said John Banyene, a civil society coordinator for North Kivu province.

“The consequences are dramatic for the inhabitants of Goma and the displaced populations of North Kivu,” he said.