The virus has killed a number of prominent politicians, and low vaccination rates have left the country vulnerable to more contagious variants.
"Several others were left wounded and 25 people were abducted, while over 70 shelters and stores were set on fire. In Boga town alone, 31 women, children and men were killed," UNHCR spokesman Babar Baloch told reporters in Geneva.
Houses were burned and civilians abducted, the U.N. office for humanitarian affairs said in a statement.
Several minutes of heavy gunfire alerted a group of conservation rangers guarding workers on the scrubby slope above.
Goma sits on the mountain's southern flank and overlooks Lake Kivu.
A historically Ugandan Islamist group, the Allied Democratic Forces is the bloodiest of scores of armed militias that roam the mineral-rich zone, many of them a legacy of two regional wars from 1996 to 2003.
A policeman was killed on Thursday as rival Muslim groups fought over the right to celebrate the Eid festivities marking the end of Ramadan at a major sports stadium, officials said.
Chitenji Kamanga, 28, was killed when the U.N. base in the village of Kilia, was attacked at 13:30 local time, the Malawi Defence Force (MDF) said in a statement.
A spokesman for a monitor called the Kivu Security Tracker (KST) said however that it had counted "only five bodies so far".
Zoe Kabila was stripped of his job as governor of Tanganyika.
Violence has remained endemic in eastern Congo since the official end of the civil war in 2003, but insecurity has soared in the past two years.
The new government of the Sacred Union coalition has 57 members including 14 women, with only 10 from the previous cabinet being reappointed.