WASHINGTON, Aug 29 (Reuters) - President Barack Obama spoke by phone to German Chancellor Angela Merkel on Thursday about Syria, the White House said, as the United States seeks the broadest possible international backing to respond to a chemical weapons attack in Syria.
White House spokesman Josh Earnest gave no details of the phone conversation. Obama said on Wednesday that the United States has concluded that the Syrian government of President Bashar al-Assad was responsible for the Aug. 21 attack, which killed hundreds in a Damascus suburb.
Earnest said the Obama administration is still on track to release details of an intelligence report aimed at showing why Washington is certain the Syrian government was behind the chemical weapons use.
Senior U.S. officials are to brief congressional leaders later on Thursday in an unclassified session. (Reporting by Steve Holland; Editing by Vicki Allen)