The White House on Wednesday said there was "no alternative to a political solution" as talks between the Syrian government and opposition forces began in Switzerland.
"There is no alternative," White House press secretary Jay Carney said.
The talks, brokered by the United Nations, hope to begin an end of hostilities in Syria, where a bloody three-year conflict has left tens of thousands dead.
Earlier this week, photographs of dead bodies that appeared to have been tortured and abused by forces of Syrian President Bashar Assad appeared, intensifying pressure to reach a diplomatic solution that removes Assad from power.
Carney said that while the White House could not independently verify the photographs, they could not "be ignored or dismissed."
"We stand with the rest of the world in horror at these images that have come to light, and we condemn in the strongest possible terms the actions of the Assad regime and call on it to adhere to international obligations with respect to the treatment of prisoners," Carney said.
He also said that the White House would not rule out military action against the Assad government, emphasizing that the U.S. "cannot intervene militarily in every civil war."
"But we can do what we have done in this case, which is work with international partners to help try to bring about a negotiated political settlement," Carney said.