WASHINGTON: US President Barack Obama spoke to Turkish President Tayyip Erdogan on Tuesday, offering US assistance as Ankara investigates last week's attempted coup but urging the government to show restraint as it pursues those responsible for the overthrow bid.

White House spokesman Josh Earnest said the two leaders discussed the status of US-based Turkish cleric Fethullah Gulen, whom Erdogan has accused of being behind the coup attempt and whose extradition Turkey has said it will seek.

Earnest said the Turkish government had filed materials in electronic form with the US government, which US officials were reviewing. He said any extradition request from Turkey, once submitted, would be evaluated under the terms of a treaty between the two countries.

Know more: US cleric Fethullah Gulen behind coup plot

Turkey's foreign minister had said on Saturday he had made clear in a call with US counterpart John Kerry that followers of US-based cleric Fethullah Gulen were behind the coup attempt, but had not directly discussed the cleric's possible extradition.

A faction of the armed forces, deemed by the government as loyal to Gulen, tried to seize power using tanks and attack helicopters overnight. One hundred and sixty-one people were killed, including many civilians, in the ensuing violence.

“The topic of extradition did not come up directly in our conversation yesterday. However, I said very directly once again that this was an attempt by Gulen, who is residing in their country, and his structure within the military,” Mevlut Cavusoglu had said in an interview in Ankara.