One of the party's co-leaders at this time was Boris Nemtsov, the party's most influential and talented mediator and a leading Russian opposition figure. Nemtsov had been one of Russia's leading economic reformers in the 1990s and also served as first deputy prime minister under President Boris Yeltsin. Nemtsov was assassinated in Moscow on 28 February 2015, being shot by an attacker in a car while on a bridge by the Kremlin. He died hours after appealing for support for an upcoming protest in Moscow against the war in Ukraine, and in a recent interview, Nemtsov had said he feared president Putin would have him killed because of his opposition to the war in Ukraine. Ukrainian president Petro Poroshenko described Nemtsov as "a bridge between Ukraine and Russia" and added "the murderers' shot has destroyed it. I think it is not by accident".