The United States and Russia issued a presidential joint statement saying there was "no military solution" to the war in Syria after their leaders met briefly on the sidelines of a regional summit in Vietnam, reports AFP.

There had been mixed messages for days from both Moscow and the White House on whether President Donald Trump and his Russian counterpart Vladimir Putin would hold face-to-face discussions during the APEC summit in Danang.

The pair were seen sharing cordial handshakes and brief conversations three times during the summit but there were no sit-down talks between the two. The statement, issued by officials from both sides, said the two presidents had made progress on Syria, which has been battered by six years of civil war.

The US and Russia have backed competing factions in the bloody conflict, and agreement between them on the next steps towards peace is rare. "The presidents agreed that there is no military solution to the conflict in Syria," the statement said, adding that the two sides "confirmed their determination to defeat ISIS" -- an alternative name for the Islamic State jihadist group.