The United States has decided to call explicitly for Syrian President Bashar al-Asad to step down, officials said Thursday, as Washington groped for ways to stop a deadly protest crackdown. The expected announcement would come as the Obama administration presses for tougher international sanctions on a regime bent on crushing a pro-democracy movement. The White House said President Barack Obama and Turkish Prime Minister Recep Tayyip Erdogan agreed during a phone call Thursday on the need for a "transition to democracy" in Syria. The Obama administration has been steadily ratcheting up pressure on Assad, who has been deaf to growing international calls to stop a crackdown that human rights groups say has killed more than 2,000 people since mid-March. "The United States is looking to explicitly call for Asad to step down. The timing of that is still in question," according to a US official who did not rule out that the announcement could come next week. "It's part of steps to increase the pressure given the ongoing brutality of the Assad regime," the official told AFP on the condition of anonymity. Another US official, who also asked not to be named, said the call for Assad's resignation could come as early as Thursday. When CBS News asked Clinton in an interview why Washington does not urge Assad to go, Clinton replied "it’s important that it’s not just the American voice. And we want to make sure those voices are coming from around the world." Then she called for concrete action against Asad, suggesting that China and India should impose energy sanctions on Syria and that Russia must stop selling arms to Damascus, which has been a customer of Moscow's for decades. "What we really need to do to put the pressure on Asad is to sanction the oil and gas industry. And we want to see Europe take more steps in that direction," Clinton said. "And we want to China take steps with us. We want to see India, because India and China have large energy investments inside of Syria. We want to see Russia cease selling arms to the Asad regime," the chief US diplomat said. On top of earlier targeted measures against Asad, regime officials and others, the United States on Wednesday imposed sanctions on the state-owned Commercial Bank of Syria and the largest mobile phone operator, Syriatel. The Obama administration has also welcomed a tougher Arab stand against Syria. In a highly symbolic move, Arab heavyweight Saudi Arabia as well as Kuwait and Bahrain withdrew their ambassadors this week from Damascus. US officials like Clinton and UN envoy Susan Rice have said that Assad has lost his legitimacy to rule, but Washington has so far resisted issuing a direct call for him to leave power. Steadily escalating US rhetoric against Asad, including a warning that he is now a source of regional instability, has fueled expectations that the Obama administration will soon formally call for him to go. But the White House Wednesday stuck with a rhetorical formulation towards Syria adopted last week, saying the country would be a "better place" without Assad. When they held their first meeting with Clinton on August 2, Syrian dissidents urged Obama to call on Asad to quit power and pressed for UN sanctions over the regime's crackdown on protests. One of the dissidents said such a high-profile US call for Assad to step down would bring more protesters into Syria's streets. Aaron David Miller, a former Middle East expert for several administrations, said the Obama team appears to have long debated the benefit of such a call but has finally faced up to the "glaring" contradiction with its Libya policy. In Libya, the Obama administration has been calling for months for Moamer Kadhafi to step down, only to see him hold onto power in the face of a NATO-led air assault in support of armed Libyan rebels. "Words are important," Miller told AFP, adding that the United States had to call for Asad to step down to show consistency in support for democratic revolts across the Arab world. "The administration needs to do this to maintain its own credibility," he said.