KASSERINE, Tunisia — Tunisia imposed a nationwide overnight curfew Friday in response to growing unrest as protests over unemployment across the country descended into violence in some cities.

The week of increasingly violent demonstrations was triggered Sunday when a young man who lost out on a government job climbed a transmission tower in protest and was electrocuted. The suicide more than five years ago of another unemployed youth set off a popular uprising that overthrew Tunisia’s longtime ruler and eventually gave rise to the ‘‘Arab Spring’’ uprisings across North Africa.

Tunisia built the only democracy to survive that movement, which spawned chaos elsewhere in the region. But the country’s economy is foundering, and about one in three young people remains without work.

A curfew from 8 p.m. until 5 a.m. was declared because the attacks on property ‘‘represent a danger to the country and its citizens,’’ the Interior Ministry said.

Associated Press