France, Oct. 2 -- Around 400 of France's 3,700 secondary schools were closed on Friday on the orders of police prefects, with many schools switching to online lessons.

Education Minister Edouard Geffray urged parents to intervene, warning that young people were putting themselves at risk.

"Children are in danger on the streets," he told BFMTV. "Parents must, quite clearly, take action and tell their children not to go [to the blockades]."

The protests began over staffing, funding and school conditions and have spread rapidly across the country.

The Interior Ministry said 1,027 secondary schools were affected on Thursday, including 222 that were blockaded. Around 30 university campuses were also blocked.

It said 1,949 people were arre...