The Qatar-based directors of Syria International Islamic Bank (SIIB) have resigned their roles at the behest of the Gulf Arab state's central bank, to comply with US Treasury sanctions against the lender.

SIIB, formed in 2006 by Qatari and Syrian investors, was designated under anti-weapons proliferation laws by the US government on Wednesday, freezing its assets in the US and prohibiting US firms and individuals from doing business with it.

"Qatari investors in SIIB will not seek board representation and will remain passive investors," the central bank said in a statement on Thursday. "The Qatar-based directors of SIIB have resigned."

Qatar International Islamic Bank (QIIB) and Qatari investors own a combined 49-percent stake in the Syrian lender,
with a QIIB representative chairman of SIIB. Other Qatar-based board members include representatives from Private Projects Co. and Qatar Islamic Insurance Co.