Manama: A new attack on an elementary school in Bahrain has taken the toll to 23 this semester, the education ministry has said.

"An incendiary device was hurled at Toobli elementary school while students were inside," the ministry said.

No injuries were reported, but the security authorities were alerted about the incident, the ministry said.

The attack occurred on Sunday as students returned to school following the two-day weekend. According to ministry officials, the attacks, mainly on elementary and middle schools, seek to disrupt courses and exams.

The first school semester started in late September and will last until the end of January.

Bahrain has been hit by a series of clashes between protestors and anti-riot police, mainly alongside the Budaya Highway to the west of the capital and in Sitra, south to Manama.