Secretary-General Ban Ki-moon has expressed shock and condemnation at the brutal killing of Russian politician Boris Nemtsov, the United Nations spokesperson’s office confirmed today.

According to media reports, Mr. Nemtsov was gunned down on 27 February in central Moscow by unknown assailants.

In a statement issued earlier this afternoon, the UN spokesperson explained that the Secretary-General noted that an investigation into the murder had been announced by Russian authorities and that Mr. Ban expected the perpetrators to be brought to justice “swiftly.”

In addition, continued the statement, the Secretary-General wished to express his “deepest condolences” to Mr. Nemtsov’s family, friends and supporters.