The victims were transferred to Turkish hospitals near the Syrian border, a source told dpa on condition of anonymity.
The blast also resulted in unspecified material damage, the Syrian Observatory for Human Rights said.
So far, there has been no claim of responsibility.
The bombing marks the 12th such attack that has targeted areas controlled by Turkish-allied rebels in north-eastern Syria since late October, according to the Britain-based observatory.
Turkey and its allied Syrian rebels seized Tal Abyad and other areas after launching a military offensive in north-eastern Syria on October 9 against Syrian Kurdish militias there.
Two ceasefire deals, first with the United States and then with Russia, brought a pause to the Turkish operation.
Turkey regards the Syrian Kurdish People's Protection Units (YPG) as terrorists linked to separatist insurgents fighting inside its territory.
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