Rebels in the eastern Democratic Republic of Congo claim to have taken the key town of Kitshanga after three days of intense clashes with government forces.
The UN-sponsored local radio Okapi was among the first to report the fall of Kitshanga to the rebels.
Images of hundreds of people fleeing the town have also been shared on social media.
“Yes we now have Kitshanga and its neighbourhoods,” Willy Ngoma, a spokesman of the M23 rebels, told the BBC on Friday.
The BBC has approached the military for a response.
Local civil society groups and the UN forces in the country have condemned M23 military offensives which have forced more than 400,000 people to flee their homes.
Congolese Senator Francine Muyumba has called on parliament to hold an extra-ordinary session because “the country is doing very badly”, she said on Twitter.
A summit held in November in neighbouring Angola had asked the M23 rebels to cease hostilities and withdraw from areas it had captured.
But the rebels said they find themselves “obliged to intervene to stop another genocide” against ethnic Tutsis living in DR Congo, according to a statement on Thursday evening.
Kitshanga town lies in a strategic route between the region's economic hubs of Goma and Butembo.
For some years, the town was the stronghold and the headquarters of the infamous rebel leader Laurent Nkunda and his CNDP rebel group, which later became M23.