"Our main priority now is to reach every house that has been damaged to ensure we can rescue any person who may be trapped," François Habitegeko, governor of Rwanda's Western Province, told Reuters.
Alain Mukurarinda, Rwanda's deputy government spokesperson, said fatalities had risen to 129 by 3:30p.m. local time (01:30 GMT)
"Our main priority now is to reach every house that has been damaged to ensure we can rescue any person who may be trapped," said Habitegeko.
The hardest-hit districts in the Western Province were Rutsiro, with 26 dead, Nyabihu with 19, and 18 each in Rubavu and Ngororero, he said.
"The soil was already soaked from the previous days of rain, which caused landslides that closed roads," Habitegeko said.
The Rwanda Meteorology Agency has forecast rainfall above the average in May for the East African nation.
In neighboring Uganda near the border with Rwanda, six people died overnight into Wednesday in an area in the southwestern Kisoro district, after heavy rains pounded the mountainous region, according to the Uganda Red Cross.
Five of the dead are from one family, and emergency workers have begun excavations to retrieve the bodies, the Red Cross said in a statement
Uganda has also been experiencing heavy and sustained rains since late March and in recent days landslides have been reported in other elevated areas, like Kasese near the Rwenzori mountains, where deluges and floods destroyed homes and displaced hundreds.