Mass shootings in New Zealand: What we know so far

At least 40 people have died in mass shootings at two mosques full of people attending Friday prayers in New Zealand.

Here is what we know so far:

:: Two mosques in Christchurch were targeted, with the deadliest shooting unfolding at the Al Noor mosque in the city centre.

:: Prime Minister Jacinda Ardern has confirmed that 40 people have died, and said: "It is clear that this can now only be described as a terrorist attack." She called it "one of New Zealand's darkest days".

:: Thirty people were killed at the Al Noor mosque and 10 were killed at the Linswood mosque.

:: A further 20 people have been seriously injured.

:: A number of improvised explosive devices strapped to vehicles have been made safe.

:: Footage on social media appears to show a gunman live-streaming as he entered a mosque with his weapon drawn.

:: Witnesses said the shooting at the Al Noor mosque lasted for 20 minutes, with the gunman going from room to room.

:: Three men and one woman are in custody, and police say there may be other attackers at large.

:: One of the arrested suspects is Australian, the country's Prime Minister Scott Morrison confirmed.

:: Large parts of Christchurch were placed in lockdown following the shootings, including schools. Police are now beginning to gradually lift these restrictions.

:: Mosques nationally have been told to shut their doors, with worshippers warned not to visit until further notice.

:: Bangladesh's cricket team was approaching the mosque for Friday prayers at the time of the shooting at the Al Noor mosque.

:: Police are still treating the incident as ongoing, and the public is still being urged to stay indoors.