Billionaire investor George Soros on Monday blasted Republican presidential candidates Donald Trump and Ted Cruz by name, accusing the pair and others of deliberately stoking terror fears.

In an op-ed article published in the Guardian newspaper, Soros, a major Democratic donor, argued that ISIS is operating from a position of weakness as its grip on its home territory weakens, but acknowledges that coming up with a resolution to the threat posed by terrorists and by the Syrian conflict isn’t easy.

“But one idea shines through crystal clear: it is an egregious mistake to do what the terrorists want us to do,” he wrote. “That is why, as 2016 gets underway, we must reaffirm our commitment to the principles of open society and resist the siren song of the likes of Donald Trump and Ted Cruz, however hard that may be.”

Trump earlier this month called for a “total and complete shutdown” of Muslims entering the U.S. Cruz and other Republican presidential candidates have criticized President Barack Obama for not referring to terror attacks in Paris and San Bernardino, Calif., as “radical Islamic terrorism.”

Terror groups like ISIS and al-Qaida know that stoking the fear of death can lead citizens and leaders of open societies to think and behave irrationally, Soros wrote.

The terrorists’ “ultimate goal” is to convince Muslim youth around the world that there is no alternative to terrorism, Soros wrote.

Terrorist attacks are designed to achieve that goal by awakening and magnifying “latent anti-Muslim sentiments in Europe an America, inducing the non-Muslim population to treat all Muslims as potential attackers,” he said.

“And that is exactly what is happening. The hysterical anti-Muslim reaction to terrorism is generating fear and resentment among Muslims living in Europe and America. The older generation reacts with fear, the younger one with resentment; the result is a breeding ground for potential terrorists,” Soros said.