Armed police secure mosques around the country amid fears attack not isolated to Christchurch

Armed police are standing guard at various mosques around the country after a series of attacks in Christchurch.

Four people have been arrested after the simultaneous attacks at Linwood and Hagley mosques, with improvised explosive devices also discovered and disabled.

Forty-nine people have been confirmed dead with many more injured.

Police Commissioner Mike Bush told media they weren't treating the incidents as isolated, with fears other regions could be targeted as well.

At Dunedin's Al Huda mosque, armed police have been stationed at the entrance since mid-afternoon.

Members of the armed offenders squad were also seen searching outside and inside the mosque during the afternoon.

Another raid took place in Somerville St, Waverley, with reports that search may relate to a vehicle connected to the Christchurch incidents - however police are yet to confirm that.

The mosque is situated in the student district, in Clyde St, with many young university students living nearby.

Students told Newshub they're concerned for their own safety and are staying indoors.

The Otago Muslim Association has urged the Muslim community to stay calm and be extra vigilant.