DUBAI, United Arab Emirates (AP) Iranian demonstrators defied a heavy police presence Sunday night to protest their countrys days of denials that it shot down a Ukrainian passenger plane carrying 176 people, the latest unrest to roil the capital amid soaring tensions with the United States.

Videos posted online showed protesters shouting anti-government slogans and moving through subway stations and sidewalks, many around Azadi, or Freedom, Square after an earlier call for people to demonstrate there. Other videos suggested similar protests were taking place in other Iranian cities.

Protesters often wore hoods and covered their faces, probably to avoid being recognized by surveillance cameras. Some online videos purported to show police firing tear gas sporadically, though there was no immediate wholesale crackdown on demonstrators.

Meanwhile, in an emotional speech before parliament, the head of the Revolutionary Guard apologized for the shootdown and insisted it was a tragic mistake.

I swear to almighty God that I wished I was on that plane and had crashed with them and burned but had not witnessed this tragic incident, said Gen. Hossein Salami. I have never been this embarrassed in my entire life. Never.