India, July 9 -- US President Donald Trump appeared to confuse Ukrainian President Volodymyr Zelensky with Russian President Vladimir Putin and misidentified Iran as an "Islamic Republic of Japan" during a press conference at this week's NATO summit in Ankara, a pair of verbal slips that quickly circulated on social media and reignited questions about the 80-year-old leader's mental sharpness.

The mix-ups unfolded Wednesday as Trump fielded questions from reporters while seated beside Zelensky on the sidelines of the summit, where NATO leaders have spent the week debating defence spending, military support for Ukraine and the future of transatlantic security amid Russia's ongoing invasion.

Gesturing toward the Ukrainian leader, Trump as...