In an interview with Fox News channel's 'Sunday Morning Futures', Mr Trump was asked about his controversial decision to pause support for Kyiv as it fends off Russia's full-scale invasion, Sky News reports.
Mr Trump, who had a disastrous meeting with Mr Zelenskyy at the White House last week, was asked about a warning from Polish President Andrzej Duda "that without American support, Ukraine will not survive".
Asked if he was "comfortable" with that outcome, the US president said: "Well, it may not survive anyway.
"But we have some weaknesses with Russia. You know, it takes two," Mr Trump added.
It comes as Mr Zelenskyy will visit Saudi Arabia for a Monday meeting with Crown Prince Mohammed bin Salman, while Ukrainian diplomatic and military representatives will meet with a US delegation on Tuesday.
The US paused military aid and the sharing of intelligence with Ukraine this month after a meeting between Mr Trump and Mr Zelenskyy on 28 February descended into acrimony in front of the world's media.
