"The preliminary report indicates that the number is likely to increase from the reported seven but we are yet to establish the actual numbers," Uganda Red Cross spokeswoman Irene Nakasiita said in a statement.
Nakasiita described the situation as tense with "community members... scared and fleeing from their homes."
"In the meantime, the whole district, Bududa is still experiencing heavy downpour and we are expecting more of the same in other landslide-prone areas."
Bududa district in the foothills of Mount Elgon, which lies on the border between Uganda and Kenya, is a high-risk area for landslides.
At least 100 people were reported killed in a landslide in Bududa in March 2010 and in 2012 landslides destroyed three villages.
Government efforts to move vulnerable people to neighbouring districts have faced resistance from residents.
(With inputs from agencies.)