More than 2,300 Syrians have fled into Turkey since Wednesday as UN chief Ban Ki-moon warns the crisis is escalating.
The figure is more than twice the highest previous one-day total in March, when more than 1,000 people crossed over the border.
The new arrivals were taken to a refugee camp in Reyhanli in 44 minibuses, he said.
More than 42,000 Syrians have fled the country since the beginning of the revolt, which has killed more than 9,000 people.
Syrian President Bashar al-Assad, who is fighting to crush a year-long uprising, agreed late last month to an UN-Arab League peace plan which sets a 10 April deadline for a ceasefire.
But there has been little sign of his adherence to the deal, while the opposition say the leader is stalling for time to make gains on the ground.
A UN team has arrived in Damascus to negotiate the possibility of deploying UN monitors to oversee any ceasefire.
Meanwhile, Turkish Prime Minister Recep Tayyip Erdogan said yesterday that he did not trust President Assad to comply with the peace plan.