UN Secretary-General Ban Ki-moon has condemned the murder of Russian opposition leader Boris Nemtsov, who was shot dead by unknown attackers in Moscow.
"The Secretary-General was shocked by and condemns the brutal killing of Boris Nemtsov in Moscow on 27th February," the United Nations press office said in a statement.
It added that Mr Ban "notes that an investigation into this murder has been announced, and he expects the perpetrators to be brought to justice swiftly."
It said he expressed his condolences to Nemtsov's family, friends and supporters.
Skepticism surrounds the suspects arrested in the Kremlin-led investigation into the death of Russian politician Boris Nemstov.
The mother of murdered Boris Nemstov's girlfriend is worried her daughter is being treated as if she had something to do with the killing.
The death of Boris Nemtsov hits particularly hard because he represented what post-Communist Russia might have become.