The Turkish military says it has surrounded the Kurdish-held city of Afrin in northern Syria, the focus of an offensive against a Kurdish militia.
A statement said troops and allied Syrian rebels had also captured “areas of critical importance” in the surrounding Afrin region.
There was no immediate confirmation from local Kurdish officials.
The operation aimed at driving the People’s Protection Units (YPG) militia out of Afrin began on 20 January.
The Turkish government says the YPG is an extension of the banned Kurdistan Workers’ Party (PKK), which has fought for Kurdish autonomy in south-eastern Turkey for three decades.
The YPG denies any direct organisational links to the PKK – an assertion backed by the US, which has provided the militia and allied Arab fighters with weapons and air support to help them battle the jihadist group Islamic State (IS).