Police shut down central avenues in the Greek capital on Monday morning as a two-day visit of Chinese President Xi Jinping got underway.
The road closures concern Syntagma square, the Presidential Mansion and the area around the Acropolis Hill.
The Syntagma metro station will remain closed and trains will pass through without stopping.
An annual parade by school children to mark Greece's rejection of an Italian ultimatum and its entry into World War II on October 28, 1941, was underway in central Athens on Monday.
The parade, which takes place in front of the Parliament on Syntagma Square, started at 11 a.m.. Streets in the surrounding area are closed to traffic until it is finished.
"The tall doorman in the green suit" is how most people who work, live or frequently pass through Syntagma Square in downtown Athens know Dimitris Taktikos, even though they don't know his name. Taktikos has stood at his post in front of the elegant entrance of the Grande Bretagne for the past 35 years.
Transport authorities are mulling the reopening of the section of the Athens tram network that runs between the neighborhood of Neos Kosmos and downtown Syntagma Square which was suspended last October amid concerns that the ground beneath the tracks was at risk of subsiding.
According to officials, fears about the potential risks were exaggerated.
Police in Athens on Tuesday were questioning two Iraqi nationals in connection with the knifing of a kiosk worker on Monday night near Syntagma Square.
One of the two men is alleged to have stabbed the employee while robbing the kiosk on Vasilissis Amalias Avenue.
A customer at the kiosk also sustained minor injuries during the incident.