During a tense and chaotic standoff with protestors at the May Day Occupy protests in Oakland, California, police threw flashbang grenades to scatter demonstrators at the intersection of 14th street and Broadway.

Police used two or three of the crowd control devises, which give off a disorienting and load explosion and a flash of light when detonated. Police also used tear gas to disperse a group of 200 or so protestors, according to Buddy Roark, 24, who was at the demonstrations.

Occupy Oakland protestors became too familiar with flashbangs in October, when Iraq war veteran Scott Oslen was hit in the head with a grenade that many witness say was thrown directly at him and other protestors.

The impact fractured Olsen's scull and put him in a coma, from which he eventually recovered. Oslen, who has filed a claim against the Oakland police department, attended the protests on Tuesday, but only as an observer, according to Mother Jones.