Rwanda-backed rebels in eastern Congo claimed Friday to have seized a second airport in the region following a days-long advance, as the U.N. warned that the recent escalation of fighting with government forces has left 350,

The Rwanda-backed rebels who seized a major city in eastern Congo have declared a unilateral ceasefire, citing humanitarian grounds. But, there was no sign of them giving up control of Goma at the heart of a region home to trillions of dollars in mineral wealth.

Rwanda-backed M23 rebels captured a strategic airport in the Democratic Republic of Congo, expanding their stranglehold over the country’s mineral-rich eastern region.