UNITED NATIONS, Sept 20 (Reuters) - United Nations Secretary-General Ban Ki-moon accused the Syrian government on Tuesday of killing the most civilians during the country's five year conflict and said "powerful patrons that keep feeding the war machine also have blood on their hands."

In his final address to the annual gathering of world leaders at the United Nations, Ban said the Syrian government "continues to barrel bomb neighborhoods and systematically torture thousands of detainees."

(Reporting by Michelle Nichols; Editing by Chizu Nomiyama) ((michelle.nichols@thomsonreuters.com; +1 646 223 6117; Reuters Messaging: michelle.nichols.reuters.com@reuters.net; Twitter: @michellenichols))