With numerous senior members of Iran's government stricken by the novel coronavirus, Revolutionary Guard leader Hossein Salami made a public statement raising the possibility that the outbreak is the result of a US bioweapon attack (archived). On January 3rd the USG assassinated Iranian Quds Force Major General Qassem Soleimani inside Iraq while there on diplomatic business at Iraq's invitation. Iran retaliated with precision ballistic missile strikes on USG positions in Iraq which the USG humiliatingly could not answer with anything other than token sanctions.
While Salami is merely raising the possibility of USG culpability at this point, the USG's credibility on the international stage is locked into a steep downward spiral.