"We don't know if a coup government would honor the agreement the USA worked out with Turkey" which has allowed the USA military to work with Kurdish militants in northern Syria to push back Islamic State fighters, Heras said.
It seems the country may have reached that breaking point already.
"Those who stain the military's reputation must leave", he said.
Turkey last endured a coup d'etat on February 28 1997.
Generals were accustomed to playing a dominant role in the Turkish state, after carrying out four military coups from 1950 to 2000. There were no tanks in the streets, as had been the case with the previous coups in the country in 1960, 1971 and 1980, but it nevertheless successfully overthrew the government of the time.
NATO's chief says all alliance personnel and military units in Turkey are "safe and secure" following the attempted coup.
Istanbul authorities sought to make a show of normalisation with the bridges reopening to traffic and Ataturk International Airport - which had been shut down by the plotters - gradually reopening.
Turkey's once-powerful military has long considered itself the guardian of the secular state founded by Mustafa Kemal Ataturk in 1923. Check with your airline as the airports might be closed to arrivals and departures.
If successful, the overthrow of President Tayyip Erdogan, who has ruled Turkey since 2003, would amount to one of the biggest shifts in power in the Middle East in years. Large crowds responded to his call and filled the main squares of Istanbul, Izmir - where I was - and the capital city, Ankara.
The surprises kept coming.
It was not clear who was behind the failed coup.
A faction of the army then declared that a "peace council" was running the country, and there would be a curfew and martial law.
A group within Turkey's military has engaged in what appeared to be an attempted coup, the prime minister said, with military jets flying over the capital and reports of vehicles blocking two major bridges in Istanbul.
More than 250 people have been killed overall.
Supporters of Tukish President Tayyip Erdogan celebrate after troops involved in the coup surrendered, in the resort town of Marmaris, Turkey July 16, 2016.
In the early hours of Saturday, lawmakers were hiding in shelters inside the parliament building, which was being fired on by tanks.
At one point Erdogan effectively addressed the nation via a video calling service, appearing on the smart phone of a CNN Turk reporter who held it up to a studio camera so that viewers to the network could see him.
According to Reuters, 29 colonels and five generals among 1,563 members of the armed forces were arrested in the wake of the coup attempt. Anadolu reported that helicopters have opened fire at the national intelligence headquarters in Ankara. Hours earlier, as the coup attempt got under way, his office declined to say where he was and he was forced to give an interview over FaceTime to a television station.
More than 2.5 million Britons visit Turkey every year.
A surreal, short-lived failure it may have been, but this incident was nonetheless one of the most significant challenges to Turkey's civilian democracy in years.
Erdogan put the blame the coup on supporters of his arch-foe, US-based Turkish cleric Fethullah Gulen, whose Hizmet movement and its powerful presence in Turkish society, including the media, police and judiciary. "The government should be won through a process of free and fair elections, not force".
According to the Guardian, the Association of British Travel Agents said there are 50,000 Britons now on holiday in Turkey, and have warned that the situation remains "fluid".
Iran said the attempted military coup in Turkey was "doomed to fail".