Several gunshots were fired early Monday at the U.S. Embassy in the Turkish capital, Ankara, from a vehicle, police and the embassy's spokesperson said. No casualties were reported.

Ties between Ankara and Washington have been strained over the case of an imprisoned American pastor, leading the U.S. to impose sanctions, and increased tariffs that sent the Turkish lira tumbling last week.

A police officer told Reuters at the scene the drive-by shooting occurred around 5 A.M. local time and that nobody was hurt. The embassy is closed this week for a public holiday to mark the Islamic Eid al-Adha festival.

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"We can confirm a security incident took place at the U.S. Embassy early this morning. We have no reports of any injuries and we are investigating the details," said David Gainer, the embassy spokesperson.

"We thank the Turkish National Police for their rapid response."

Police teams were searching for the assailants, who fled in a white car after the attack, CNN Turk said. Four or five gunshots were heard, it said, one hitting a window in a security cabin but causing no casualties.

Video footage from broadcaster Haberturk showed police teams inspecting one of the entrances to the embassy and apparent damage caused by a gunshot could be seen in one window. It said empty cartridges were found at the scene.

The U.S. embassy in Ankara and the consulate in Istanbul have been the targets of attacks by militants and have faced numerous security threats in the past.