President Obama was greeted by protesters in Athens on Tuesday. Riot police clashed with the rally-goers.

Protesters hurled molotov cocktails, rocks and other items from behind makeshift barricades. Police responded with tear gas and stun grenades. The clashes erupted when a group of protesters tried to break through police cordon lines to reach the parliament building and the US embassy.

About 7,000 people marched in central Athens holding banners and making anti-American chants. Anti-war, anti-racism and leftist groups joined communist party supporters and labor union members to protest.

People angry over the US stance on the war in Syria, American relations with Turkey and the election of Donald Trump also came in droves.

U.S. President Barack Obama (L) reviews a presidential honor guard during the official welcoming ceremony at the presidential palace in Athens, Greece, Nov. 15, 2016. U.S. President Barack Obama arrived in Athens Tuesday for a two-day visit amid draconian security measures as his trip marks the first to the country by a U.S. leader since 1999. (Xinhua/Marios Lolos)