Turkish authorities are preparing to absorb a large wave of refugees as violent clashes continue in northern Syria.
Turkey is setting up a field hospital at the site of one of the refugee camps that have been established in the border area.
More than 4,000 Syrians have crossed the border into Turkey to escape the violent crackdown on protests against Syrian President Bashar Assad and thousands more are gathering near the border, officials and activists said on Saturday.
Turkish authorities are trying to prevent refugees from moving deeper into Turkish territory and from making contact with relatives in the region.
Turkish authorities are also working to maintain the normal flow of traffic between Turkey and Syria, parallel to the influx of refugees.
Fearing revenge from Syrian security forces for clashes in which Syrian authorities said 120 troops were killed this week, refugees streamed out of the northern town of Jisr al-Shughour ahead of a military operation launched by the army there on Friday.
A senior Turkish diplomat said 4,300 Syrians had crossed the border and that Turkey was prepared for a further influx, though he declined to predict how many might come.
"Turkey welcomed a great many number of guests in the past in their times of most dire need. We can do that again," Foreign Ministry Deputy Undersecretary Halit Cevik was quoted as saying by state-run Anatolian news agency.
Just inside Syria, thousands of people have gathered close to the border, according to an activist helping coordinate the movement of refugees.
"The border area has turned practically into a buffer zone," said the man, who identified himself only as Abu Fadi. "Families have taken shelter under the trees and there are 7,000 to 10,000 people here now."
Human rights groups say Syrian security forces have killed more than 1,100 Syrian civilians in an increasingly bloody crackdown on demonstrations calling for Assad's removal, more political freedoms and end to corruption and poverty.
Thirty-six protesters were shot dead across Syria on Friday, activists said. Syrian authorities deployed helicopter gunships in the town of Maarat al-Numaan, they added, in the first known use of air power against unrest.
Syria has banned most foreign correspondents from the country, making it difficult to verify accounts of events.
The northwest border area, like other protest hot spots, is prone to tension between Syria's majority Sunni Muslims and Assad's Alawite sect, which dominates the Syrian power elite. The recent clashes hint at splits within the security forces, whose commanders are mainly Alawite and conscripts Sunni.
Want to enjoy 'Zen' reading - with no ads and just the article? Subscribe todaySubscribe now