Two senior United Nations officials have been recalled from Ethiopia after audio recordings containing criticism of senior U.N. officials was released online, according to a letter and a U.N. Population Fund (UNFPA) spokesperson.

In the recordings, two women who say they work for the U.N. in Ethiopia but do not give their names tell a freelance journalist that some top U.N. officials globally sympathise with forces from the northern Tigray region that are fighting Ethiopia's government.

Reuters heard the women's comments after the recordings were released online but could not independently verify the authenticity of the recordings.

In a letter dated Oct. 11, the head of the International Organisation for Migration (IOM) said a staff member had been recalled to headquarters and put on administrative leave pending an investigation into the recordings.

"The opinions attributed in the audio recordings to the staff member do not correspond to IOM's principles and values," IOM Director General Antonio Vitorino wrote in the letter, seen by Reuters on Tuesday.

In his letter, Vitorino did not name the person who had been recalled. Two U.N. staff members in Addis Ababa identified one of the women in the recording as Maureen Achieng, the IOM's chief representative in Ethiopia.

Asked whether the person recalled to headquarters was Achieng, an IOM spokesperson said they could not confirm the name of any staff.

Achieng and the journalist could not immediately be reached for comment.

Two U.N. officials based in East Africa identified Dennia Gayle, the U.N. Population Fund's country representative in Ethiopia, as the other voice in the recording.

A UNFPA spokesperson said its representative to Ethiopia had been called back to New York for further discussions. The spokesperson did not provide a name.

Gayle did not respond to requests for comment sent by email and on Twitter late on Tuesday.

"Senior management is deeply concerned and this matter is currently being dealt with in line with our internal rules and regulations," the spokesperson said.

"All UNFPA staff are bound by the United Nations standards of independence and neutrality, which are vital to our work delivering for all the people we serve - no matter who or where they are," the spokesperson added.

The U.N. says Ethiopia's government is preventing aid from reaching hundreds of thousands of people experiencing famine in Tigray, where war has made nearly 7 million people dependent on food aid. The government denies it is blocking aid.

Ethiopia last month decided to expel seven senior U.N. officials, accusing them of meddling in internal affairs.

Prime Minister Abiy Ahmed's spokesperson, Billene Seyoum, criticised IOM on Twitter on Tuesday. She said Achieng - whom she referred to by linking to Achieng's verified Twitter account - had told "the unvarnished truth on institutional bias with the U.N. system".

War broke out in November 2020 between the Ethiopian government and the Tigray People's Liberation Front (TPLF), the political party that controls Tigray.

In the recordings, the two women say - without citing evidence - that World Health Organization chief Tedros Adhanom Ghebreyesus is among the U.N. officials who sympathise with Tigrayan forces. Tedros, who is Tigrayan, has repeatedly denied taking sides in the conflict.