ATHENS, Greece (AP) — Minor clashes broke out in Athens Tuesday as left-wing demonstrators protesting a visit by President Barack Obama tried to break a police cordon and were repelled with tear gas.

No injuries or arrests were reported. About 3,000 anarchists, left-wing group supporters and students marched through the city center in a demonstration originally planned to reach the U.S. Embassy in another part of town.

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A second planned Athens protest by Communist party supporters was due to start later Tuesday.

All demonstrations have been banned in a large swathe of central Athens during Obama's two-day visit. Riot police blocked the marchers from the part of the city where Obama will be, parking buses across roads and manning cordons.

Greek authorities have deployed more than 5,000 police for Obama's visit. The riot squad is on high alert for violence, and an armed anarchist group has called for "attacks and clashes" to disrupt the visit.

There is a strong anti-American tradition among Greek left-wingers who still resent U.S. support for Greece's 1967-74 military dictatorship.

Obama's visit comes just two days before the country's main annual anti-American demonstrations, which commemorate the bloody suppression, by military authorities in 1973, of a pro-democracy student uprising.

The last visit to Greece by a U.S. president was by Bill Clinton in 1999. It was marred by extensive street fighting between anarchists and riot police.