Russia on Monday condemned the killing of Iran’s top nuclear scientist last week. “We express our serious concern over the provocative nature of this terrorist act, which is clearly aimed at destabilizing the situation and building up conflict potential in the region,” the foreign ministry said in a statement. “We call on all parties to refrain from taking steps that could lead to an escalation of tensions.” Iran said on Monday that Israel and an exiled opposition group used new and "complex" methods to assassinate Mohsen Fakhrizadeh, seen by Tel Aviv as the "father" of Irans nuclear weapons program Fakhrizadeh died Friday after his car and bodyguards were targeted in a bomb and gun attack on a major road outside the capital, heightening tensions once more between Tehran and its foes.