Four people are in custody relating to the Christchurch mosque shooting, but New Zealand police warn there could be more offenders.

Three of them are men with one woman.

About 300 people were inside the mosque for afternoon prayers and 27 have been confirmed dead.

Witnesses told New Zealand media they ran for their lives and saw people bleeding on the ground outside the Al Noor mosque.

Authorities have advised all mosques to shut down until further notice and all Christchurch schools are on lockdown.

A live video appearing to be the shooting at the mosque and documents were allegedly posted online.

A vehicle which is alleged to belong to the gunman was found with several guns it in which had writings on it, reportedly explaining the reason behind the mass shooting.

Stuff.co.nz reports the emergency department at Christchurch Hospital has been cleared out.

Hospital staff are expecting about 40 to 50 injured people, and private hospital Southern Cross has also been cleared to treat the injured.

Meanwhile, Former FBC journalist Roland Koroi, says they have been instructed by police to stay indoors.

Koroi who lives in Hornby with his family says they are just 15 minutes away from where the shooting took place.

In her recent presser, Prime Minister Jacinda Arden has urged people to remain on lockdown even if it means families are separated.

Arden says this is one of New Zealand’s darkest day as it is an extraordinary and unprecedented act of violence.

She is expected to hold another presser later this afternoon.

Source: FBC News