But Peter Cook";s remarks left many questions unanswered about when and how Washington learned about it.

'It's fair to say that the attempted coup was a surprise to us as it was to people in Turkey and elsewhere,” he said.

'I do not know the first inclination that our folks had that something was going on, but obviously they had publicly available information over the news media in Turkey that something was happening,” he added, referring to American forces at the Incirlik Air Base in the southern Turkish city of Adana.

Cook said the U.S. military has taken measures to protect American troops and assets at the base but Defense Secretary Ash Carter has yet to speak to his Turkish counterpart.

Conversations between Turkish and American militaries continued throughout the course of events last week but Cook declined to specify at what levels talks took place as nearly all top commanders of the Turkish Armed Forces were captured by coup plotters.

Cook tried to deflect any suggestion of a rift with regard to why the defense chiefs have not yet spoken days after the attempted coup. 'There's no significance to that, other than they just have not spoken,” he said.

As the Turkish government continues to purge coup plotters from state institutions, claims have surfaced by senior Turkish authorities that the U.S. might have been involved in the coup attempt.

The role of Incirlik in the coup attempt might have triggered those claims.

Turkish authorities have said coup plotters used the air base as main station for the takeover attempt. Air refueling tankers used in the coup were launched form the base where3,000 U.S. troops and U.S. aircraft are stationed in anti-Daesh operations.

According to Cook, the U.S. is using only one section of Incirlik and the base is Turkish – leaving American commanders unaware of any information regarding the coup.

Incirlik and Turkey will remain key to the counter-Daesh fight, Cook added, but the U.S. might make some adjustments to the anti-Daesh efforts if electricity at the base is not soon restored.

A key issue Cook failed to address was how the U.S. learned, assessed and instituted force protection measures.

Force Protection Conditions Level for U.S. forces abroad are 'updated constantly -- on a daily basis” and measures are taken 'nearly immediately” in accordance with security conditions, a U.S. defense official told Anadolu Agency, speaking on the condition of anonymity.

The military procedure did not somehow work at Incirlik on Friday night when Turkey was in the middle of a failed coup attempt.

Starting from 10 p.m. Turkish time (GMT1900), several Turkish jets were launched from the Akincilar Air Base near Ankara and flew above Turkey";s capital and Istanbul, alongside several attack helicopters and tanks.

Shortly after, authorities announced that a coup attempt was in progress.

The defense official told Anadolu Agency, however, that the European Command 'made the decision for Force Protection Condition Level Delta at Incirlik by 7.30 a.m. (0430GMT) Saturday local time” when actually the coup attempt was nearly over.

Level Delta is the highest security restriction under which no asset or personnel is allowed to enter or leave.

Two defense officials and Cook could not provide a reason to Anadolu Agency why upgrading the Force Protection Condition Level was decided so late.

Another defense official told Anadolu that even if the security level was not upgraded to the highest, there was sufficient security to protect American assets and troops.

But the question that triggered the upgrade ofthe Force Protection Condition Level is yet to be answered.