SAINT-PETERSBURG (AFP) – World leaders arrived Thursday for a dinner hosted by Russian President Vladimir Putin where they would discuss the crisis in Syria, with President Barack Obama showing up alone and well after the main group.

The main group of leaders led by Putin arrived together at the historic Peterhof palace outside Saint Petersburg, with British Prime Minister David Cameron and French President Francois Hollande seen talking animatedly at the back of the pack.

But Obama was nowhere to be seen and only arrived at the palace a good half an hour after the rest.

Striding purposefully through the palace park, he smiled and waved for the cameras, images broadcast by the organizers showed.

Also arriving late, showing up to the dinner just before Obama, was Brazilian President Dilma Rousseff.

It was not immediately clear why they lagged behind the main group.

Putin said earlier that the G20 leaders would have the chance at the dinner to discuss the conflict in Syria, which until now was not on the G20 agenda.

Brazil-U.S. tensions are running high after Brasilia demanded explanations from Washington for reports that the National Security Agency (NSA) spied on Rousseff’s communications.