Greece has made a diplomatic protest to Turkey following an exchange of fire on their common border which caused no casualties, a Greek military source said.
The Greek source said it was the worst such incident for some time on the border, but did not link it to the current crisis in the two neighbours' relations over Cyprus.
Turkey also reported the shooting, which occurred on Wednesday evening, but each side accused the other of opening fire first.
Greece's army command said three Turkish border guards had fired into Greek territory, and a Greek patrol had fired back, while Turkey's Anatolia new agency gave an exactly opposite account, saying the Greek guards were drunk.
The Turkish reports said the incident occurred at the Evros River between the villages of Kuplu and Adasarhanli and blamed it on "drunkenness" by the Greek guards.
The Greek military played down the clash, saying the incident was closed, although an inquiry would be made to determine the cause. It said Athens was treating it calmly.
Turkish reports said that Turkish military officials were also investigating.
The exchange of fire came two days after the Greek Foreign Minister, Mr Theodoros Pangalos, visited the Turkish side of the north-eastern border and gave Turkish border guards chocolates and Greek brandy.
Earlier on Monday he had visited Greek border guards, then crossed the border into Turkey, where he talked to Turks. But he also used the opportunity to accuse the local Turkish consulate at Komotini of interfering in Greek affairs, a charge rejected by Ankara.
His visit came after a similar gesture by President Suleyman Demirel of Turkey, who gave flowers and sweets to Greek border guards on July 19th.
Relations between Greece and Turkey have long been tense over territorial sovereignty disputes in the Aegean Sea and over the ethnically divided island of Cyprus. In January 1996, they came close to clashing over the Greek islet of Imia in the eastern Aegean. War was averted with last-minute US intervention.
Greek coastguard boats sometimes chase away Turkish boats that they believe violate Greek waters.
On Monday last, Greek coastguard vessels fired warning shots at a flotilla of Turkish fishing boats near the eastern Aegean island of Chios.