[Police patrol outside Zappeio Conference Hall in Athens, Monday, Nov. 14, 2016. Thousands of police are to be deployed in Athens for draconian security measures during a two-day visit to Athens by President Barack Obama starting Tuesday. (AP Photo/Yorgos Karahalis)]ATHENS, Greece (AP) — Greek authorities are preparing draconian security measures ahead of a two-day visit by US President Barack Obama, including the deployment of thousands of police, road closures and restrictions on protests.