 -- Hours before the U.S. launched airstrikes against Syria, former Democratic presidential nominee Hillary Clinton spoke out Thursday about how she would respond to Tuesday's chemical attack in Syria, promoting U.S. action to prevent further attacks with civilian casualties.

Speaking at the Women in the World summit in New York City, Clinton said that the U.S. "should have been more willing to confront [Syrian President Bashar al-Assad]," before Russia got involved in the country's civil war and with Iran's participation limited to ground-based assistance.

"Assad had an air force and that air force is the cause of most of the civilian deaths as we’ve seen over the years and as we saw again in the last few days," said Clinton. "I really believe we should have and still should take out his airfields and prevent him from being able to use them to bomb innocent people and drop sarin gas on them."

ABC News' Liz Kreutz contributed to this report.