UPDATE 1-Trump's hopes for swift summit with Putin may be stalled, CNN reports

(Adds detail, context in paragraphs 2-6) Oct 20 (Reuters) – U.S. President Donald Trump's hopes for a quick summit in Budapest with Russian President Vladimir Putin stalled after a preparatory session between the leaders' top foreign-policy aides this week was put on hold, CNN reported on Monday. Citing sources familiar with the matter, CNN said the reason for postponing the meeting between U.S. Secretary of State Marco Rubio and Russian Foreign Minister Sergei Lavrov was unclear. One source cited differing expectations about ending Russia's war in Ukraine, CNN said. Rubio and Lavrov may talk on the phone again this week, CNN reported, after the two held a call on Monday that Moscow called "constructive." Russia's foreign ministry could not immediately be contacted outside business hours.