JOHANNESBURG (REUTERS) - South African police have arrested five people on suspicion of murder for botched circumcisions that led to the deaths of about 30 boys in coming-of-age rituals in the rural Eastern Cape province, a police spokesman said on Monday.

Police were also investigating suspected assault, gross bodily harm and unlawful circumcisions that left 300 others injured across the province over the last week, police spokesman Sibongile Soci said.

Every year in South Africa, boys aged 10 to 15 from several of the country's tribal groups are circumcised in traditional "initiation rituals". The ceremonies usually take place over a number of weeks in remote rural areas.

Deaths are mainly caused by blood loss or infection from circumcisions poorly performed by traditional practitioners.

The ruling African National Congress called the deaths and injuries "tragic" and said the government must act immediately.

"Authorities can no longer pay lip service to dealing with this disaster that afflicts our nation during the traditional initiation season," it said in a statement.

In May, more than 20 youths died in the northern Mpumalanga province, prompting rare cross-party calls for reform of a practice ingrained in local culture.