Mamdani is on course to win the Democratic primary after Tuesday's election, beating predictions.
Ukrainian leader steps up diplomatic push, while his Russian counterpart will skip a summit due to ICC arrest warrant.
Archbishop Bagrat Galstanyan, a leader in protests against the PM, is accused of a plot to overthrow the government.
Despite claiming that Tehran does not have the capacity to make nuclear bombs, the IAEA may have ratcheted up tensions.