Dhaka, March 21 -- Iran's Foreign Minister Abbas Araghchi said on Thursday that a recent letter sent by US President Donald Trump calling for new nuclear talks was "actually more of a threat", and that Tehran would respond soon.Araghchi told Iranian state television that while the letter purported to offer up opportunities, it was "actually more of a threat", adding that Iran was now studying its contents and would respond "in the coming days".On March 7, Trump said he had written to Iran's supreme leader Ayatollah Ali Khamenei calling for negotiations and warning of possible military action if Iran refused.Khamenei said the US invitation to talks was aimed at deceiving world public opinion by portraying the United States as ready to negoti...