By Justin Sink - 03/28/13 07:20 PM EDT
The Associated Press reported Thursday that mortar shells slammed into a cafeteria in the building, killing 15 people and wounding another 20. There was no immediate claim of responsibility, but the attack in Damascus — which has remained relatively untouched by the violence that has left tens of thousands of Syrians dead — represented an escalation in the country's civil war.
"We understand that they hope to begin their investigation within the next week," Earnest said. "So we're certainly pleased to see the U.N. moving quickly to work out the details. And it demonstrates the unique importance the United Nations is placing on the investigation."
The White House also called on the Assad regime to assist investigators as they examined the attack.
"This investigation is only going to be successful if the Assad regime cooperates with their efforts to investigate any and all credible allegations of the possible use of chemical weapons in Syria," Earnest said. "So we're hopeful that the Assad regime will cooperate with the group."