Numerous previous Nigerian presidential election petitions have not succeeded.
The US was outspoken in its criticism of alleged atrocities by Ethiopian forces and their allies.
Lagos city's Yoruba people protested against non-indigenes whom they accused of trying to take over the state.
South Africa insisted on impartiality in Russia-Ukraine war and abstained from UN resolution voting condemning Russia.
The rate of fatalities could rise in first half of 2023, the report said.