US President Donald Trump warned on Friday that the United States may walk away from peace talks between Russia and Ukraine if either side blocks the ceasefire process. This echoes concerns expressed by Secretary of State Marco Rubio. If negotiations stall, Trump said the US would stop facilitating a deal without specifying which country is hindering progress. He suggested that if one party makes it difficult to reach an agreement, the US will reject it.
Source: https://www.politico.eu/article/us-ukraine-ceasefire-doable-marco-rubio