The latest effort to end the brutal and bloody war in Syria opens Wednesday in Switzerland, but experts have little hope for a breakthrough.
U.S. Secretary of State John Kerry and Russian Foreign Minister Sergei Lavrov are leading the talks, along with the United Nations and representatives of the Syrian government and the main opposition.
But Syria's main regional ally, Iran, will not be there. U.N. Secretary General Ban Ki-moon canceled Iran's invitation when it refused to accept the goal of a transitional government in Syria - one that likely would exclude President Bashar al-Assad.
Lavrov called Ban's decision a mistake, but not a disaster. He says Iran's presence was essential for success.
Expectations for a breakthrough at the talks are low. President Assad has said he will not give up power.
The peace conference begins as smuggled Syrian police photographs emerged Tuesday. They show sickening images of what are said to be Syrian victims of torture, starvation, beatings and strangulation.
One war crimes lawyer says the pictures remind him of images from Nazi death camps.
State Department spokeswoman Marie Harf says the pictures are extremely disturbing and horrible to look at. She says they illustrate actions that would be serious international crimes.
Civilians gather after what they said was shelling by forces loyal to Syrian President Bashar al-Assad, Jazmati, Aleppo, Jan. 23, 2014.
Civilians carry belongings from rubble after what activists said was shelling by forces loyal to Syrian President Bashar al-Assad, Jazmati, Aleppo, Jan. 23, 2014.
This citizen journalism image provided by Aleppo Media Center shows Syrian residents and rescue workers carrying an injured man after an airstrike in Aleppo, Jan. 23, 2014.
A Free Syrian Army fighter holds a dead bird as his comrades inspect the damage caused by what activists said were barrel bombs dropped by government forces in Jabal al-Akrad, Latakia, Jan. 23, 2014.
Free Syrian Army fighters rest in front of a graffiti that reads 'Surely your Lord's assault is strict indeed' in the old city of Aleppo, Jan. 22, 2014.
Free Syrian Army fighters stand along a deserted street filled with garbage and rubble in the old city of Aleppo, Jan. 22, 2014.
Residents inspect a damaged site after what activists said was an air strike by forces loyal to Syria's President Bashar al-Assad in Karam Al-Beik, Aleppo, Jan. 21, 2014.
Smoke rises from what activists said were explosive barrels thrown by forces loyal to Syria's President Bashar al-Assad in Jabal al-Akrad, Latakia, Jan. 20, 2014.
Men react as others rush at the site of a car bomb attack at the Bab al-Hawa border crossing between Syria and Turkey, in Idlib, Jan. 20, 2014.
Men transport a casualty after car bomb attacks at the Bab al-Hawa border crossing between Syria and Turkey, in Idlib, Jan. 20, 2014.
Some information for this report was provided by AP, AFP and Reuters.