Turkish President Recep Tayyip Erdogan has repeatedly accused its NATO ally, the United States, of supporting the Islamic State.

The Turkish president said on Dec. 27 that the U.S. gives support to terrorist groups including the Islamic State. “It’s very clear. We have confirmed evidence, with pictures, photos and videos,” the Turkish president added.

State Department spokesman Mark Toner responded to these remarks that day by calling them “ludicrous.”

“No basis for truth, as you can all imagine. I don’t think anyone could look at our actions on the ground leading the coalition in northern Syria, in Iraq and say anything other than that we’re 100 percent behind the defeat, destruction of Daesh,” Toner said, using another name for the Islamic State.

Turkish journalist Abdullah Bozkurt reported that Erdogan repeated this claim again Friday basing it off a distortion of an interview by retired Army Gen. Wesley Clark. Just a few days prior, Şamil Tayyar a lawmaker part of Erdogan’s ruling Justice and Development Party (AKP) said that the CIA was behind the New Year’s nightclub attack in Istanbul that ISIS took credit for.

A State Department official told The Daily Caller Monday: “We note with concern that Turkish media and Turkish officials have made incendiary and false accusations that the United States in some way facilitated this attack. These allegations are false, and the people spreading these allegations are distorting the truth. Such false stories threaten both the ties between our nations and the safety of our citizens.”

And according to Turkish journalist Bozkurt, Erdogan said Monday that he can’t “bring myself to call [US & NATO] as friends.”

“This is absurd,” Christopher Preble, vice president for defense and foreign policy studies at the Cato Institute, told The Daily Caller. “This guy is peddling conspiracy theories that are believed by large numbers of Turkish citizens going back to the allegation that the United States was behind the coup attempt in July.”

Following the failed July coup, Erdogan said that Army Gen. Joe Votel, the head of Central Command, was on the “coup plotters’ side” and added that the U.S. was “nurturing” American-based Muslim cleric Fethullah Gülen, who he claims was the coup plotter. Turkey has requested the U.S. extradite Gülen, but Preble said the Obama administration is doing the right thing by not complying as Gülen is doubtful to face a fair trial.

Preble didn’t like that incoming White House national security adviser Michael Flynn has taken Erodgan’s side regarding Gülen. And while Preble said Trump’s questioning of the modernity of NATO is “short-sighted,” he did say Erdogan’s actions raise “some various serious questions about what exactly is the value of this NATO ally?”

Preble added, “What is the value of the NATO alliance that we should come to the defense of a country that is so decisively anti-American?”

The accusation that the U.S. supports ISIS is not limited to Erdogan. Democratic Hawaii Rep. Tulsi Gabbard, a member of the House Committees on Foreign Affairs and Armed Services, said in December that the United States is funding and arming al-Qaida and the Islamic State. She said this support was through the CIA “funneling weapons and money through Saudi Arabia, Turkey, Qatar and others who provide direct and indirect support to groups like ISIS and al-Qaeda.”

Hillary Clinton gave a 2013 speech to Goldman Sachs in which she said American allies Saudi Arabia, Qatar and the United Arab Emirates are supporting ISIS. President-elect Donald Trump also said several times on the campaign trail that President Barack Obama was the “founder” of ISIS. “He was the founder. His, the way he got out of Iraq was that that was the founding of ISIS, OK?,” Trump said on an August radio show.