Weekly Standard - A Republican lawmaker is urging the president to block a multibillion-dollar deal between Boeing and Iran Air that is now facing steep sanctions from the Trump administration.

The Obama administration lifted its sanctions on Iran Air and permitted commercial jet sales to Iran under the nuclear deal. But the airline has not stopped its illicit activities, Illinois congressman Peter Roskam wrote in a letter to Trump Friday.

Roskam�s letter goes hand in and with the Treasury Department�s�designation ofIran�s Islamic Revolutionary Guard Corps (IRGC) for terrorism on Friday, citing its support for the Quds Force, the IRGC�s overseas arm.

That support includes sending personnel and military equipment to Syria�activities that Iran Air, which has a deal with Boeing for 80 commercial jets, was previously�sanctioned�for. �Iran Air has shipped military-related equipment on behalf of the IRGC since 2006,� a 2011 sanctions designation reads.

�Iran Air continues transporting troops and weapons to Syria, while remaining sanction-free and able to buy hundreds of new aircraft to bolster its terror-supporting operations,� Roskam wrote. �Iran Air serves as a lifeline to the Assad Regime.�

Treasury�s Friday designation says that the IRGC has used civilian airports in Iran, as well as military bases, to ferry military equipment into Syria and Iraq for the IRGC Quds Force.

After delisting Iran Air in 2016, the Obama administration would not guarantee that the airline had stopped engaging in illicit activities. Commercial jets, Roskam noted, are still "military-fungible."

�It is scandalous that the Obama Administration, who sold sanctions relief under the JCPOA as solely being nuclear-related, decided to delist Iran Air without requiring the carrier to cease its support for terrorism, clearly illicit and sanctionable activity,� he wrote, using an acronym for the nuclear deal.

Trump said in a speech Friday that the administration�s crack down on Iran �begins with the long-overdue step� of slapping harsh sanctions on the IRGC.