Obama made the remarks during a joint news conference with Turkish Prime Minister Recep Tayyip Erdogan at the White House on Thursday.
The US president said Washington will make efforts to mobilize the international community to exert more pressure on Assad.
Meanwhile, Erdogan said that Ankara will support the militants in Syria and that Assad’s removal from power is one of Turkey’s priorities.
“We both agree that Assad needs to go. He needs to transfer power to a transitional body,” Erdogan stated.
“That is the only way we’re going to resolve this crisis,” he added.
However, at a meeting in Washington on Monday, Obama and British Prime Minister David Cameron promised to make diplomatic efforts to find a political solution to the two-year crisis in Syria.
The Syria crisis began in March 2011, and many people, including large numbers of soldiers and security personnel, have been killed in the violence.
The Syrian government says that the chaos is being orchestrated from outside the country, and there are reports that a very large number of the militants are foreign nationals.
In an interview broadcast on Turkish television on April 5, Assad said that if the militants take power in Syria, they could destabilize the entire Middle East region for decades.
“If the unrest in Syria leads to the partitioning of the country, or if the terrorist forces take control… the situation will inevitably spill over into neighboring countries and create a domino effect throughout the Middle East and beyond,” he stated.
Source: Press TV