Cops have arrested three self-proclaimed anarchists for allegedly assaulting two officers and terrorizing patrons at an East Village Starbucks.

The melee broke out Saturday at 8:45 p.m., when a gang of 25, some wearing masks and wielding metal pipes, tried to smash the windows of the coffee shop at Astor Place and Lafayette Street, police said.

Customers hid under tables during the attack.

The group had just left the sixth annual anarchist book fair at a church off of Washington Square Park.

They then began marching against traffic, chanting obscenities about cops.

An NYPD sergeant and lieutenant were treated for minor injuries.