Iran suggested on Monday that it might withdraw from the new peace talks on Syria because of what Iranian officials described as the unconstructive role of Saudi Arabia, Iran’s rival for dominance in the Middle East.

It was unclear whether the suggestion, carried via state-run news media, was serious or more akin to diplomatic posturing, since Iran would have much to lose if it were to leave talks it has long sought to attend.

The Iranian warning came three days after representatives from Iran and Saudi Arabia sat in the same room for the first time at a formal diplomatic meeting in Vienna of nearly 20 countries, including Russia and the United States, aimed at finding a way to end the Syrian civil war, now in its fifth year.

Little was decided at that meeting except that Syria’s territorial integrity must remain intact and that participants would reconvene within a few weeks.