BEIJING — At least five men armed with knives burst into the dormitory of a vocational college Wednesday and slashed nine students, one of them seriously, sparking new fears in a country on edge over a series of shocking rampages at schools.

Four students had been wounded in an earlier confrontation between the two groups, bringing the total injured to 13.

The predawn attack took place in Haikou, the capital of the southern island province of Hainan, when five or six men burst into a dormitory at the Hainan Institute of Science and Technology and slashed the students, the China News Service reported.

It said eight were wounded slightly, while one’s hand was cut off.

The attack follows five separate assaults by lone assailants against schoolchildren in the last two months that have left 17 dead and more than 50 wounded, including some adults.