Kenya has, once again, demanded the "urgent release" of Yassin Juma, a journalist arrested in Ethiopia last month.
An Ethiopian court had ordered him freed on bail but authorities are yet to do so.
In a letter to the Ethiopian Foreign Ministry, Kenya termed the continued detention of Mr Juma, who contracted Covid-19 in prison last week, as a violation of his rights to justice.
The letter seen by the Nation says Ethiopian authorities should have freed Mr Juma, real name Collins Juma Osemo, on August 5 as ordered by a court after he deposited bail of $85 as directed.
"The Ministry is deeply concerned that despite the decision of the court, Mr Osemo is still in police custody," it says in the letter dated August 12.
"The continued detention of this Kenyan national despite the decision of the court and payment of bail is highly regrettable and has caused immense anguish and anxiety to him, his family, the people and the government of the Republic of Kenya."
However, despite protests from Nairobi, Mr Juma has been held for more than a month now.
In a handwritten letter to the Nation, Juma expressed fears over his deteriorating health while in detention.
He was arrested on July 3 in the house of prominent Ethiopian media mogul Jawar Mohammed. Juma, other journalists and several politicians are accused of crimes related to subverting authority.
They are also accused of fomenting violence in the wake of the assassination of popular Ethiopian musician and activist Hachalu Hundessa.
His detention has raised uproar among Kenyan activists as well as global rights bodies Human Rights Watch, Amnesty International and the Committee to Protect Journalists (CPJ).
They have all demanded his, and other journalists' release.
On Sunday, Mr Abdulletif Amee, one of three Ethiopian lawyers defending Mr Juma, said he will be back in court for another hearing today (Tuesday). This is the same court whose orders Ethiopian police have defied, however.
Juma is now under quarantine within the Sostegna Police Station where he is being held after he was arrested early in July. His lawyers say they are defending Mr Juma without being pay.
On August 5, Ethiopia's Federal First Instance Court ordered release of the defendant on 3,000 birr ($85) bail after prosecutors failed to provide concrete evidence for his case.
However, Ethiopian police have ignored the order, raising questions about the court's supremacy.