Congressional appropriators released March 2 a defense spending bill that would prevent President Donald Trump's administration from sending shoulder-fired anti-aircraft missiles to Syrian rebels in the latest showdown between the House and Senate over the issue.

Section 9013 of the fiscal year 2017 bill, a compromise between House and Senate appropriators, simply states that "none of the funds made available by this Act under the heading ‘Counter-ISIL [Islamic State] Train and Equip Fund' may be used to procure or transfer man-portable air defense systems [MANPADS]." The restriction clashes with the annual Defense authorization bill that President Barack Obama signed into law in December; that legislation for the first time explicitly allowed the Pentagon to deliver such weapons to vetted rebel groups, under certain conditions.

"If Trump decides not to end American military support for the rebels, providing MANPADS could help the opposition maintain its positions in Idlib," Syrian opposition adviser Bassam Barabandi told Al-Monitor in December. 

The March 2 spending bill would make that difficult by shutting off one of the main sources of funding for US military operations in Syria. According to an explanatory statement of the bill released by House Appropriations Chairman Rodney Frelinghuysen, R-N.J., the House initially included the funding ban while the Senate did not.