Four asylum seekers were detained by federal agents on Tuesday at San Francisco Immigration Court, a move the Department of Homeland Security has portrayed as part of a broader return to "the rule of law" but that immigration attorneys have called unconstitutional and unprecedented in U.

Over 100 immigrant rights advocates protested outside San Francisco’s immigration court to oppose recent ICE operations conducted within court premises. (AP Video: Haven Daley)

The arrests are part of a controversial tactic where ICE agents wait in the hallways of immigration courts to detain people as they are leaving.