Attacks on two mosques in New Zealand which left at least 49 people dead on Friday -- the Muslim day of prayer -- have sparked horror, revulsion and dismay around the world.
"It is clear that this can now only be described as a terrorist attack," said Prime Minister Jacinda Ardern, describing it as "one of New Zealand's darkest days."
"It's obviously very sad. It recalls painful memories of our own experience with July 22, the most difficult moment in the post-war period in Norway."
Malaysian Prime Minister Mahathir Mohamad said he hoped New Zealand "will arrest these terrorists and do the necessary under the law of the country."
"The brutal attack... will never diminish the tolerance and decency that New Zealand is famous for."
British Prime Minister Theresa May offered deepest condolences "after the horrifying terrorist attack in Christchurch. My thoughts are with all of those affected by this sickening act of violence."
London's police service said it was "stepping up reassurance patrols around mosques and increasing engagement with communities of all faith, giving advice on how people and places can protect themselves."
German Chancellor Angela Merkel said she mourned "with New Zealanders for their fellow citizens who were attacked and murdered out of racist hatred while peacefully praying in their mosques. We stand together against such acts of terrorism."