Donald Trump has stated that if Moscow or Kyiv "make it very difficult" to strike a peace deal, the US will "take a pass" on brokering future Russia-Ukraine negotiations, BBC reported.

Trump told reporters in the Oval Office on Friday that he did not anticipate a truce to be reached in "a specific number of days," but that he wanted it done "quickly." 

His remarks came hours after US Secretary of State Marco Rubio warned that discussions will be abandoned unless significant signs of progress were seen within days. "We're not going to continue with this endeavour for weeks and months on end," Rubio said, adding that the US has "other priorities to focus on", according to BBC.

This comes as Russian attacks on Ukraine continue, with two people killed and more than 100 injured in the north-eastern cities of Kharkiv and Sumy on Friday.