President Barack Obama is asking Congress for $500 million for a Pentagon mission to arm and train moderate Syrian rebels.
Syria's more moderate rebels are battling both the Syrian regime and the Sunni radical fighters who have taken over much of neighboring Iraq.
Those Islamist radicals are known as ISIL or ISIS. That stands for the Islamic State of Iraq and the Levant, but it can be translated as the Islamic State of Iraq and Syria.
ISIS is trying to create an Islamic caliphate based on harsh Sharia law that spans both sides of the Syria-Iraq border.
Obama's cautious approach to Syria has come under increased criticism as the four-year-long civil war spills across the border into Iraq. Critics argue the president's reluctance to arm moderate rebels years ago gave ISIL the space to grow stronger.
The new military program would be supplemented by $1 billion to help Syria's neighbors deal with huge numbers of refugees and the threat of extremists.
Meanwhile, the UN's humanitarian chief, Valerie Amos, warns that conditions in Syria are still deteriorating.
She says hundreds of thousands of civilians in besieged areas are still without basic aid. Almost 11 million Syrians are now in need of humanitarian assistance.