Newsweek has learned that Abdullah Qardash has been designated as the successor to ISIS leader Abu Bakr al-Baghdadi, who died during a U.S. raid Saturday.
"Does the president not trust the Speaker of the House with sensitive national security information?" Chris Wallace asked.
"Al Baghdadi spread 'fire and brimstone' on earth; now he feels it for himself in hell," GOP Senator Mitt Romney tweeted.
Trump appeared to suggest Thursday that the Kurdish population in Syria relocate to a small area of desert he referred to as the "Oil Region."
The president said Wednesday that the U.S. would now "let someone else fight over this long bloodstained sand."
James Franklin Jeffrey told the Senate Foreign Relations Committee on Tuesday that the government does not know exactly how many Islamic State militants have been freed.
The president has come under fire from Republican lawmakers over his Syria troop withdrawal, allowing Turkey's invasion of Kurdish areas.
New Jersey Democratic Senator Bob Menendez said it's no coincidence that Russia continues getting foreign policy victories over the Trump administration.
"If we abandon the Kurds, ISIS will come back and if there's an attack here or against our allies, President Trump owns it," the Republican senator said.
"This is a complete and utter national security disaster in the making and I hope President Trump will adjust his thinking," the Republican senator tweeted.
Newspapers "Moskovsky Komsomolets" and "Rossiyskaya Gazeta" have criticized the move by the U.S. president, who is now seeking to impose sanctions on Turkey.
"We should in a bipartisan way seek to ... change Turkey's behavior," Democratic Representative Eric Swalwell said.
"We've set the conditions for ISIS 2.0 ... and we're repeating the mistakes of the Obama administration, which pulled out of Iraq too soon and led to all of this in the first place, except we won't have any local allies to fight them again," Michael Waltz said.
The South Carolina senator and Trump ally slammed the president last week over the withdrawal of U.S. military support in Syria.
It comes as further criticism was heaped on President Donald Trump—his actions described as "careless and callous" by former diplomat Brett McGurk.
Democratic Rep. Adam Schiff joined several GOP lawmakers in condemning President Trump's U.S. troop withdrawal from Syria, warning that ISIS is already beginning its resurgence.
"We've won. We've beat ISIS and we've beat them badly and decisively," the president told reporters last week.
"There is a project to eradicate Kurds," SDF spokesman Mustafa Bali said. "Therefore, our first duty is the protection of our people, border and soil."
Thousands of ISIS fighters are being held by Kurdish-led forces in northeastern Syria, but the Turkish assault threatens the security of the detention centers there.
The lack of regulation for private channels attracts terrorist groups, who use Telegram to message recruits, spread propaganda, fundraise and orchestrate violent attacks, according to the Counter Extremism Project.
"The only way this actually ends is when we protect ourselves against those who would threaten us," Jack Keane said.
"I don't understand how a president that claims he's the toughest President ever would do such a weak move like this," Representative Adam Kinzinger said.
"This is heart-rending for anybody who has shed blood, who has deployed forward," former NATO Supreme Allied Commander James Stavridis said.
Some 2,500 ISIS foreign fighters remain in Kurdish prisons in northeastern Syria, but the Turkish operation may threaten the security of such facilities.
Allowing Turkey to act against the Kurdish-led SDF in northeastern Syria "will severely damage American credibility," retired General Joseph Votel said.
"The fight against Daesh [ISIS] is not over and continues alongside the [Kurdish-led] Syrian Democratic Forces," Prime Minister Edouard Philippe said.
"We are voluntarily abdicating our role and it's the Russians, Iranians and others who are benefitting," Richard Haass warned.
The former U.S. Ambassador to the United Nations said the decision was "appalling" because Kurds had been "promised our partnership."
The president told reporters Monday that an unnamed "top general" lamented the state of U.S. military supplies when he took office.
An intelligence official told Newsweek about Trump's phone call with the Turkish leader, saying the U.S. president was "out-negotiated."