(CNN) The White House's announcement that US forces in northern Syria would move aside in advance of a planned Turkish military offensive came as a surprise to almost everyone, including some of the President's Republican allies in Congress.

Sens. Mitch McConnell, Lindsey Graham, Ben Sasse, Susan Collins, and Mitt Romney lambasted Trump's decision, arguing that the move would leave Kurdish allies exposed to an imminent attack from Turkey.

In defending his decision, Trump tweeted Monday that he wanted to effectively wipe his hands of the ISIS conflict, and suggested that while the Kurds were allies in the fight against ISIS, they no longer needed further aid. "The Kurds fought with us," Trump tweeted, "but were paid massive amounts of money and equipment to do so."

Facts First: The US has provided some equipment and weapons to Kurdish forces and paid monthly stipends ranging from $100 to $400 per soldier. While the definition of "massive" is nonspecific, the annual amount given to the Kurds is far less than the billions of dollars the Pentagon spends on foreign military aid to other countries.

According to the Congressional Research Service , through September 2018 the US spent $28.5 billion on the overall fight against ISIS in Syria and Iraq since 2014. The Kurds played a key role in that fight.

Melissa Dalton, a senior fellow at the Center for Strategic and International Studies, told CNN that from fiscal year 2017, when the US began earnestly supporting forces in Syria to fight ISIS, through the 2019 fiscal year, the US has provided $1.4 billion toward equipment, supply, training and stipends for these partners.

"It has directly contributed to the ability of US local Syrian partners to eliminate the territorial control of the Islamic State," Dalton said.

These partners in Syria are mostly made up of Kurdish fighters who were formerly part of the Kurdish People's Protection Unit (YPG).

For the 2020 fiscal year, Trump requested $300 million "to continue to equip and sustain Syrian partner forces." The proposed assistance includes 3,000 AK-47 rifles, ammunition, hand grenades, explosives, bulldozers, and non-tactical vehicles as well as monthly stipends ranging from $100 to $400 per soldier.

The fight against ISIS

According to the Pentagon, this assistance to the Kurdish-led Syrian Democratic Forces (SDF) and other fighters is "a crucial part" of the US strategy to "support the lasting defeat of ISIS."

In an August 1 statement , Ambassador James F. Jeffrey, the Special Envoy for the Global Coalition to Defeat ISIS, said around 10,000 terrorist fighters were being held in camps in northeast Syria "by the SDF with some support from [the] US."

Al-Hol, one of these camps managed by the Kurdish-led SDF, currently holds some 70,000 individuals displaced by the fight against ISIS.

According to the Washington Post, 30,000 of these individuals remain loyal to ISIS -- SDF leaders told The Post the risk of ISIS taking control of the camp is high.

Henri Barkey, an adjunct senior fellow for Middle East studies at the Council on Foreign Relations, told CNN the situation at the camps managed by Kurdish forces in Syria contradicts the President's claim that the Kurds have received "massive amounts of money," noting their struggle to man and guard the prison camps due to a lack of funds.

In its statement Sunday, the White House announced that "Turkey will now be responsible for all ISIS fighters in the area captured over the past two years in the wake of the defeat of the territorial 'Caliphate' by the United States." It's unclear what this means for the SDF-controlled camps.

How does this compare to aid provided to other countries?

In 2017 , the Department of Defense spent a total of approximately $13 billion in foreign aid. According to USAID, Iraq, Afghanistan and Israel each received slightly over $3 billion.

The year prior, the US also committed to providing $38 billion in military aid to Israel spread out over 10 years.

The DOD's overall 2019 budget is $686 billion.