Turkey's Prime Minister Recep Tayyip Erdogan has met Turkish speakers in Greece in a first visit there by a Turkish leader for more than 50 years.
Erdogan said his visit was a lesson of friendship to all
Mr Erdogan urged hundreds of people in the northern region of Thrace who came to welcome him to preserve their heritage while contributing to Greece.
Many Thrace residents say their linguistic, religious and educational rights are being denied by Greece.
The visit comes as both Greece and Turkey try to end decades of tensions.
It follows Mr Erdogan's talks in Athens with the Greek Prime Minister, Kostas Karamanlis, where both leaders pledged to leave behind suspicions of the past and engage in a strategic partnership.
But the divided island of Cyprus remains a sticking point between the two countries, correspondents say.
Greek-speaking Cypriots rejected a UN plan for reunification in a referendum on 24 April, while Turkish-speaking Cypriots backed it.
"My presence here must be a lesson (of friendship) for all people," Mr Erdogan said in the northern town of Komotini, about 70 kilometres (42 miles) from the Turkish border.
"I'm specially addressing my brothers. You will, without doubt, protect your special identity. Nobody is telling you to lose or give up your Turkish identity. But don't forget you are citizens of Greece," he said.
The mainly Turkish-speaking communities in Thrace - estimated at about 120,000 - have been a symbol of the long-standing rifts between Athens and Ankara.
The region came under Ottoman control in 1363, but became part of Greece in 1920.
In 1923, the two countries agreed a population exchange, which allowed some 110,000 ethnic Greeks to remain in Istanbul and some 115,000 ethnic Turks in Thrace.
The last time a Turkish prime minister visited the region was in 1952.