By Fedja ‌Grulovic

SOFIA, Dec 10 (Reuters) - A Bulgarian court has rejected Lebanon's request to ‍extradite a ‌Russian shipowner linked to the 2020 Beirut port blast, citing insufficient security ⁠guarantees from Lebanese authorities.

Igor Grechushkin, a ‌Cyprus-based Russian businessman whose vessel transported the explosive material that detonated at Beirut port in August 2020, killing more than 220 people, was detained in Bulgaria in September ⁠for possible extradition to Lebanon, where he is wanted over his role in the disaster.

"According to ​the court, Lebanon did not provide sufficient evidence to ‌ensure that the death penalty will ⁠not be imposed on him or, if imposed, will not be carried out," Ekaterina Dimitrova, Grechushkin's lawyer, told reporters after the hearing which was closed ​to media.

The blast, one of the largest non-nuclear explosions in history, devastated large parts of Beirut and left tens of thousands homeless. Grechushkin was placed on Interpol’s wanted list at Lebanon's request in 2020.

Angel Kanev, the supervising ​prosecutor, ‍said he would appeal the ​ruling, arguing that Lebanon’s justice minister, Supreme Court and Prosecutor General had all provided the required guarantees.

"Given that they have been given by such an authority ... I believe that the grounds for extradition exist," Kanev told reporters.

Lebanon's probe into the causes of the blast and possible negligence by top Lebanese officials ⁠has dragged on for years, with families of the explosion's victims blaming political interference.

The first investigative judge was removed ​after charging top officials. His successor, Tarek Bitar, also charged senior politicians, who refused questioning, denied wrongdoing and froze his probe.

Bitar resumed his investigation earlier this year and has questioned several officials in ‌recent months but he has yet to issue a long-awaited preliminary indictment.

(Reporting by Fedja Grulovic and Stoyan Nenov, writing by Daria Sito-Sucic; Editing by Ros Russell)