WASHINGTON, Aug. 18 (UPI) -- President Obama called on Syrian President Bashar Assad to resign "for the sake of the Syrian people" Thursday.
"The future of Syria must be determined by its people, but President Bashar Assad is standing in their way," Obama said in a statement issued by the White House. "His calls for dialogue and reform have rung hollow while he is imprisoning, torturing and slaughtering his own people."
It was the first formal call for Assad to leave office by the White House.
"We have consistently said that President Assad must lead a democratic transition or get out of the way. He has not led," the statement said. "For the sake of the Syrian people, the time has come for President Assad to step aside."
Obama also announced "unprecedented sanctions" to further isolate Syria financially and disrupt its "ability to finance a campaign of violence against the Syrian people."
The executive order immediately freezes all Syrian assets subject to U.S. jurisdiction and prohibits individuals from any transaction involving the Syrian government.
The executive order also bans U.S. imports of Syrian-origin petroleum or petroleum products, prohibits individuals from having any dealings in or related to Syria's petroleum or petroleum products and prohibits U.S. individuals from operating or investing in Syria.
"The Assad government has now been condemned by countries in all parts of the globe, and can look only to Iran for support for its brutal and unjust crackdown," Obama said, noting the European Union also imposed sanctions and the U.N. Security Council condemned Syria's actions.
Obama's statement expressed admiration and inspiration for the Syrian people and their pursuit of a peaceful transition to democracy.
"They have braved ferocious brutality at the hands of their government," Obama said. "They have spoken with their peaceful marches, their silent shaming of the Syrian regime, and their courageous persistence in the face of brutality -- day after day, week after week. The Syrian government has responded with a sustained onslaught."
The Syrian people must determine their future, Obama said, "and we have heard their strong desire that there not be foreign intervention in their movement."
"What the United States will support is an effort to bring about a Syria that is democratic, just, and inclusive for all Syrians," he said. "We will support this outcome by pressuring President Assad to get out of the way of this transition … ."
Meanwhile, the United Nations said Assad told U.N. Secretary-General Ban Ki-moon military and police operations against protesters had ended.
Details of a phone conversation between Assad and Ban were released Wednesday, the day before the U.N. Security Council is to be briefed on Assad's crackdown against protesters calling for his ouster, CNN reported.
The United Nations was expected to propose the International Criminal Court in The Hague, Netherlands, investigate Assad and his regime for alleged war crimes.
"President Assad said that the military and police operations had stopped," the statement from Ban's office said.
Details were released after Syria's state-run media said security forces withdrew from hard-hit Latakia and Dier Ezzor, although the date of the conversation was unclear, CNN said.
Earlier Wednesday, opposition groups said at least 10 people were killed in military crackdowns in Latakia, Homs and Idlib and that Syrian forces withdrew to the outskirts of some cities, they remained in the streets of Ramel, a neighborhood in Latakia that is home to a Palestinian refugee camp.