U.S. Border Patrol agents were pelted with rocks and bottles while turning back a crowd of more than 100 people who crossed the border illegally into California, authorities said.

Agents were struck in the arms and legs, and one was hit in the head with a filled water bottle but no shots were fired and nobody was seriously hurt in Sunday’s confrontation that ended with the group retreating into Mexico, according to a Border Patrol statement.

“While attacks on Border Patrol agents are not uncommon, the agents showed great restraint when faced with the dangers of this unusually large group,” Paul Beeson, San Diego sector chief for the Border Patrol, said in the statement.

Such large-scale confrontations have rarely been seen since the 1990s, when crowds of people would storm checkpoints or gather in groups for nighttime dashes.