Turkey's government went on an arrest spree after the attempted coup

Turkish authorities have moved swiftly in the aftermath of the attempted coup to root out those who may have conspired to overthrow the government of President Recep Tayyip Erdogan on Friday night.

At least 2,800 military personnel or people suspected to be behind the coup were detained on Saturday and 2,745 judges were purged from the courts. Among those detained or removed include five generals and 29 colonels. Alparslan Altan, a member of the country's highest court, was also arrested after the coup.

As Erdogan cracks down hard on people behind what he deemed an act of treason, US President Barack Obama has warned Turkey to "act within the rule of law."

Erdogan is certain he knows who masterminded the thwarted power grab: his former ally-turned-arch-nemesis, the US-based cleric Fethullah Gülen, who has lived in exile in Pennsylvania since 1999.

Erdogan speaks on twitter:

— Mustafa Akyol (@AkyolinEnglish)July 15, 2016

As Erdogan sees it, a faction of the military, whom he deemed Gülen loyalists, tried to seize power using tanks and helicopters. "I have a message for Pennsylvania," Erdogan said on Saturday morning. "You have engaged in enough treason against this nation. If you dare, come back to your country."

In an interview with a journalist from The Guardian on Saturday, Gülen rejected those claims, and suggested instead that Erdogan had instigated the coup to use as an excuse to tighten his grip on the country.

"I don't believe that the world believes the accusations made by President Erdogan," Gülen said. "There is a possibility that it could be a staged coup and it could be meant for further accusations [against the Gülenists]."

Erdogan has long accused Gülen of making deep roots in Turkey's state structure and establishing what he called a "terrorist parallel state" – with loyalists infiltrating almost every level of government. The counterpoint to his argument that Gülen was behind the coup is that it is the national police and the judicial systems that are believed to be dominated by the cleric's loyalists, not the military. And it was the military who attempted a takeover of government

Over the last few years, Erdogan has gone on a McCarthy-style witch hunt, jailing journalists and academics suspected of having connections to Gülenists.

On Saturday, Erdogan called on Obama to either extradite Gülen to Turkey or arrest him. US Secretary of State John Kerry has said that the US would "entertain" the possibility, but that Turkish authorities would have to provide concrete information that Gülen was the ringleader of Friday's coup.