violent demonstrations at the u.s. embassy in iraq u.s. forces firing tear gas as protesters set tires on fire and try to scale the walls while iraqi security forces stand guard. late today, the iranian backed demonstrators packing up and disbursing after their militia leaders ordered a retreat. president trump sending 750 troops from the 82nd airborne to the region to counter the iranian threat after 100 marines arrived within hours of the siege. >> we had some great warriors come in and do a fantastic job when they were there instantaneously as soon as we heard. this will never ever be benghazi. >> reporter: in iraq no demonstrators made it inside the walls of the complex president trump blames the attack on iran saying he would hold them responsible but today the country's top religious leader hitting back on twitter. you can't do anything. all part of a tense stand off with iran with iranian-backed forces repeatedly targeting u.s.