The US has carried out its first air strike on so-called Islamic State in Syria from a base in Turkey, a Pentagon spokesman has said.
An unmanned aircraft – or drone – was used on Monday, Captain Jeff Davis confirmed. He did not give any specific details about the target.
The US is also preparing for strikes by manned aircraft as part of a planned offensive, Reuters news agency reports.
Last month Turkey launched its first strikes on the militants.
The drone flew out of Incirlik airbase near the southern city of Adana. It is unknown whether its first mission was successful, the BBC’s Gary O’Donoghue in Washington reports.
Armed drones began flying out of Turkey at the weekend as a result of a new agreement between the coalition and the Turkish government.
Foreign Minister Mevlut Cavusoglu had said that Turkish and US aircraft would be used in a “comprehensive battle against Islamic State”.
The two allies have been working on plans to provide air cover for US-trained Syrian rebels to target Islamic State (IS) militants on a strip of territory about 50 miles (80km) along the Turkish border, reports Reuters.
The BBC’s Selin Girit in Istanbul says there is serious opposition to any Turkish boots on the ground in Syria.
Many suggest that as Turkey only has an interim government – since the June general election – it should not take such serious decisions as engaging in a “comprehensive battle”, she adds.
Syrian Foreign Minister Walid Moualem said on Wednesday that Syria supported efforts to combat IS provided they were co-ordinated with Damascus.
“The United States contacted us before they sent in this group and said they are fighting against Daesh (IS) and not the Syrian army at all,” he said.
“We said we support any effort to combat Daesh [IS] in co-ordination and consultation with the Syrian government, otherwise it will be a breach of Syrian sovereignty.”
Tensions have increased after a series of attacks on the Turkish side of the Syrian border.
A Turkish soldier was killed in an exchange of fire with IS fighters near the border in July.
Days earlier a suicide bombing blamed on IS killed 32 people in the predominantly Kurdish town of Suruc.