Spain on Friday called on the U.N. to correct what it called mistakes in a report compiled for the U.N. by independent human rights experts, who urged the release of three jailed Catalan separatist leaders.

In an advance copy seen by Reuters, the U.N. Working Group on Arbitrary Detention said Spain should investigate the "arbitrary" decision to deny bail to Oriol Junqueras, Jordi Sanchez and Jordi Cruixart and give them a chance to seek compensation. The report argues that the detention of the trio goes against the Universal Declaration of Human Rights and the U.N.'s International Covenant on Civil and Political Rights.

The Spanish ambassador to the U.N. in Geneva has requested a correction of the report's conclusions, which Spanish government spokeswoman Isabel Celaa blamed on mistakes, omissions and conflicts of interest. The working group was made up of five experts, two of which had links to the one of the lawyers of the accused, Celaa said after the weekly cabinet meeting. "The Spanish government believes it's important that [U.N. special procedures] have transparent financing mechanisms which prevent them from being subject to manipulation, misinformation and contamination," Celaa said.

Nine former Catalan leaders are in jail while standing trial on charges of rebellion and misuse of public funds. The charges relate to their alleged role in organizing a 2017 referendum on secession and subsequent declaration of independence.