Tehran said Sunday it will keep talking with world powers on its disputed nuclear programme despite a US move to blacklist Iranian companies for evading sanctions. "We are pursuing the negotiations seriously and of course we will give a well-considered, purposeful, smart and proper reaction to any inappropriate and unconstructive move," Foreign Minister Mohammad Javad Zarif wrote on his Facebook page. This was despite the Americans having made "inappropriate moves to which we gave the appropriate response by considering all aspects of the issue".