The announcement from the humanitarian body came as Uganda and the Democratic Republic of Congo claimed to capture 34 rebels in a joint military operation in eastern DRC.
Two staff members of the International Committee of the Red Cross (ICRC) abducted last month in eastern Democratic Republic of Congo have been freed.
"We are relieved by the return of our colleagues and we rejoice that they are able to return to their families," Rachel Bernhard, head of the ICRC's delegation in Congo, told Reuters on Saturday.
"We would like to reiterate that this kidnapping and all other attacks against humanitarian personnel can endanger activities dedicated to helping communities hard hit by the conflict."
She provided no further details about the circumstances of the kidnapping or the subsequent liberation.
The ICRC said in late November that one Congolese citizen and an international staff member had been kidnapped in North Kivu province, where dozens of armed militias operate.
The United Nations and humanitarian organisations have warned about an increase in attacks on aid workers in eastern Congo.
Three employees of the UN refugee agency were injured on Wednesday in North Kivu when their vehicle came under fire.
DRC, Uganda capture 34 rebels
A Congolese-Ugandan military offensive against the deadliest militia in eastern DRC has captured 34 rebels, freed hostages and destroyed camps, the two armies said on Saturday.
Uganda and the DRC launched artillery and air strikes on November 30 against the Allied Democratic Forces, a group blamed for attacks in the Ugandan capital and regular massacres in eastern DR Congo, with Ugandan troops then entering Congolese territory.
A joint army statement on Saturday said the operations captured 34 ADF rebels, released 31 Congolese hostages and destroyed four enemy camps in " preliminary results", noting no army deaths.
"Since the launch of operations against the ADF terrorists and their local auxiliary forces, the situation remains calm on the ground," the statement added.