U.S. and European leaders are calling for Syrian President Bashar al-Assad to step down to end the violence in his country.
U.S. President Barack Obama called for Assad to leave office in a written statement from the White House.
"We have consistently said that President Assad must lead a democratic transition or get out of the way," Obama wrote. "He has not led. For the sake of the Syrian people, the time has come for President Assad to step aside."
Obama's statement is the first explicit U.S. call for Assad to resign as global pressure increases on the Syrian leader to end a months-long and bloody crackdown on dissent.
But Obama emphasized that Washington "cannot and will not impose this transition upon Syria" and vowed to heed Syrians' "strong desire that there not be foreign intervention in their movement."
The United States also announced tough new sanctions on Assad's regime in an executive order that freezes all Syrian government assets and forbids investment and exports to the country.
U.S. Secretary of State Hillary Clinton said that by banning American imports of Syrian petroleum, the sanctions on Syrian oil would "strike at the heart of the Syrian regime."
"The steps that President Obama announced this morning will further tighten the circle of isolation around the regime," she said. "His executive order immediately freezes all assets of the government of Syria that are subject to American jurisdiction and prohibits American citizens from engaging in any transactions with the government of Syria or investing in that country."
'On His Way Out'
Some analysts, however, said the U.S. sanctions are likely to have limited impact because of the low level of U.S.-Syrian trade and the minimal U.S. imports of Syrian oil.
After Clinton spoke, a senior U.S. official said the United States is certain that Assad is "on his way out.”
Washington-based Syrian human rights activist Mohammad al-Abdallah, who met with Clinton earlier this month, told RFE/RL that Obama’s statement will erase any doubt in the Syrian public's mind about the U.S. position.
“We’ve been waiting for this statement for a long time for a couple of reasons," Abdallah said. "Syrians inside Syria have this conspiracy theory. They have thought for a long time that the U.S. administration has been [supporting] the Syrian president [to] try to make a deal with him under the table. A huge part of the public was not totally convinced that the U.S. administration wanted him to leave. [So] to target him in this way, clearly and loudly, is a key thing."
Abdallah also said the U.S. call will “encourage a huge number of people from the silent majority to join the protest and support the revolution,” including businesspeople and elites.
Washington's demands for Assad to step down were followed by similar calls by British Prime Minister David Cameron, German Chancellor Angela Merkel, and French President Nicolas Sarkozy, who issued a joint statement.
The European Union also said it is time for Assad to leave office.
"The EU notes the complete loss of Bashar al-Assad's legitimacy in the eyes of the Syrian people and the necessity for him to step aside," foreign policy chief Catherine Ashton said in a statement.
Ashton also said Europe was considering new sanctions, but it was unclear whether they would go as far as the U.S. measures.
According to the U.S. Energy Information Agency, Syrian crude oil exports go mostly to Germany, Italy, and France.
Canada also today joined the call for Assad to relinquish power, while Switzerland recalled its ambassador from Damascus -- a step that several Arab nations have also recently taken.
Meanwhile, Damascus rebuked the calls for Assad to leave and warned of new violence.
Government spokesperson Reem Haddad told the French news agency AFP, “It is strange that instead of offering [Damascus] a helping hand to implement its program of reforms, the West and Obama are seeking to stoke more violence in Syria.”
New Rights Report
The stepped-up pressure from Western capitals for Assad to resign comes as UN rights officials are expected to call on the Security Council to refer Damascus to the International Criminal Court (ICC) for possible prosecution over its crackdown on protesters.
UN Human Rights Commissioner Navi Pillay is expected to make that call as she briefs the UN Security Council in New York on August 18 on a new report by rights investigators into the unrest in Syria.
The report says it found "a pattern of human rights violations that constitutes widespread or systematic attacks against the civilian population."
It says Syria may have committed crimes against humanity by conducting summary executions, torturing prisoners, and targeting children during the crackdown.
The investigation also identifies 50 alleged perpetrators at "various levels" of Assad's government and says that, as of mid-last month, at least 1,900 people have been killed in the unrest in Syria.
In an apparent effort to deflect the mounting international pressure, Assad said on August 17 that he has ordered his army and police to stop military operations and mass arrests in protesting cities.
Assad reportedly told UN chief Ban Ki-moon that he would also begin reform "in the next few months," including constitutional change and elections.
But separately, he also vowed to remain in power, telling his ruling Baath party on August 17 that Syria would "remain strong and resilient."
Activists have called for mass protests on August 19 across Syria, which they are calling, "Friday of Signs of Victory."
written by Charles Recknagel and Richard Solash, with additional reporting by Golnaz Esfandiari and agency reports