MOSCOW (Reuters) - Russian President Vladimir Putin and his U.S. counterpart Donald Trump may discuss a Syria settlement at an Asian economic summit in Vietnam next week, the RIA news agency reported on Saturday. Relations between Moscow and Washington have soured further since Putin and Trump first met at a G20 summit in Hamburg in July when they discussed allegations of Russian meddling in the U.S. election, but agreed to focus on better ties.. Tensions have risen over the conflict in Syria, after Russia vetoed a United Nations plan to continue an ongoing investigation into chemical weapons.. A Syria settlement  is being discussed  for the agenda of a possible meeting between the two presidents, Kremlin spokesman Dmitry Peskov was quoted as saying by RIA, adding it was in their common interest to have enough time to discuss the issue.  Somehow or another it requires cooperation,  Peskov said. Trump told Fox News this week that it was possible he would meet Putin during his Asia trip.  We may have a meeting with Putin,  he said.   And, again   Putin is very important because they can help us with North Korea. They can help us with Syria. We have to talk about Ukraine.  