WASHINGTON - President Donald Trump's administration has rejected Turkey's offer to condition the release of an American pastor on clearing a top Turkish bank of billions of dollars in US fines, media reported Monday.

Washington and Ankara are locked in a bitter feud over the nearly two-year jailing of Andrew Brunson over disputed terror charges, which has triggered a trade row and sent the lira into a tailspin.

In exchange for Brunson's release, and that of other US citizens as well as three Turkish nationals working for the US government, Turkey asked Washington to drop a probe into Halkbank, which is facing possible fines for helping Iran evade US sanctions. But the US said that discussions regarding the fines and other areas of dispute between the two countries were off the table until Brunson was released, a White House official told the Wall Street Journal. "A real NATO ally wouldn't have arrested Brunson in the first place," the unnamed official said.

Shots fired at US embassy in Ankara

Gunshots were fired at the US embassy in Ankara early on Monday, without causing any casualties, Turkish and American officials said as tensions spiked between the two NATO allies. Six shots were fired at the embassy with three bullets hitting the iron gate and exterior wall, the Ankara governor's office said, indicating there were "no casualties".

Turkish police detained one suspect in connection with the attack, the state-run Anadolu news agency, without providing any details. Speaking to AFP, spokesman David Gainer confirmed the embassy was investigating a "security incident".

"We have no reports of any injuries and we are investigating the details," he said, thanking the Turkish police for their "rapid response". A bullet mark could be clearly seen in the window of the security booth, an AFP journalist at the scene said. Foreign Minister Mevlut Cavusoglu condemned it as a "provocative attack" in a posting on Twitter.

"We will make sure that this incident is investigated quickly and the perpetrators are brought to justice," he said.

The Turkish foreign ministry said measures were taken to "ensure the security of the US embassy in Ankara, other US missions and their personnel" across the country.

The attack took place to the backdrop of a bitter diplomatic spat between Ankara and Washington, with presidential spokesman Ibrahim Kalin also blasted the attack as an attempt to "create chaos"

"Turkey is a safe country and all foreign missions are safeguarded by law," he wrote on Twitter.

The highly-fortified embassy was also hit by a suicide bombing five years ago that killed a Turkish security guard and injured several other people. That attack was claimed by the Revolutionary People's Liberation Front (DHKP-C), a radical Marxist group.

Ankara and Washington have been locked in an increasingly acrimonious diplomatic dispute over Turkey's detention of an American pastor on terror-related charges.

US President Donald Trump has doubled the tariffs on aluminium and steel tariffs from Turkey, prompting Ankara to impose similar measures on several US products.

On Friday, Turkey threatened to respond in kind if Washington imposed further sanctions as a court rejected another appeal to free pastor Andrew Brunson.

The diplomatic stand-off has sent the Turkish currency into free fall against dollar although President Recep Tayyip Erdogan has vowed to lead the country out of the crisis.

In a statement ahead of Eidul Azha, Erdogan remained defiant over the US sanctions. "The attack aimed at our economy has no difference from an attack aimed at our call to prayer or flag," he said.

Those who thought they could bring Turkey to its knees through the foreign currency exchange rate "will soon see they are mistaken," Erdogan added.