Here are some key takeaways from the high-stakes meeting. President Trump on Monday said the United States will be involved in security assistance for Ukraine -- a key condition for Zelenskyy in any deal to end the war -- but did not elaborate on what exactly that would look like or give any specifics.

President Donald Trump and Ukrainian President Volodymyr Zelenskyy's meeting in the Oval Office was notably different from their last encounter in February.

Ukrainian President Volodymyr Zelensky said his bilateral meeting with US President Donald Trump in the Oval Office on Monday was "very good" and "constructive," as European leaders met with the US leader to discuss security guarantees for Kiev.