At least 4,300 people have now fled violence in Syria to seek refuge in Turkey, a senior Turkish official says.
A BBC correspondent on the border says the real number of displaced people is probably much higher.
The Syrians have mainly been fleeing the town of Jisr al-Shughour, targeted in a government crackdown.
An eyewitness described a tank attack on a nearby village on Friday morning, in which people were killed and crops destroyed.
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