CHRISTCHURCH, New Zealand (AP) — A national memorial in New Zealand to commemorate the 51 people who were killed when a gunman attacked two mosques one year ago has been canceled due to concern over the new coronavirus.

Thousands of people were expected to attend the Sunday service in Christchurch to mark the anniversary of the March 15 shooting.

New Zealand has had just six confirmed cases of COVID-19. All of those cases have been connected to people returning from abroad and so far there haven't been signs of a local outbreak. The most recent case, involving a man in his 60s who recently returned from the U.S., was announced by health officials Saturday.

Prime Minister Jacinda Ardern said the decision to cancel the service at Horncastle Arena, also announced Saturday, was pragmatic and precautionary.

“We’re very saddened to cancel, but in remembering such a terrible tragedy, we shouldn’t create the risk of further harm being done,” Ardern said in a release.

The announcement came a day after Ardern had said at a news conference in Christchurch that the event would still go ahead.

Some had questioned at the time why the event was proceeding after Ardern and other officials had elected to cancel a festival in Auckland celebrating Pacific culture due to fears over the coronavirus.

Ardern had said Saturday that the Pasifika Festival was canceled out of a specific concern the virus could spread to Pacific islands that don't have the health infrastructure to cope with an outbreak.

On Friday, Ardern attended a special joint prayer with members of both mosques that were attacked.

Immediately after last year's attacks, Ardern started working on changing the nation's gun laws. The deadliest types of semi-automatics are now banned, and in a nationwide buyback, gun owners turned in about 60,000 of their newly outlawed weapons for cash.

Ardern also worked on trying to eliminate terror attacks from being shown online, after the gunman livestreamed the Christchurch attacks. Ardern brought some nations and tech companies together to work on the issue in what she named the Christchurch Call, which she said had helped start a new crisis response protocol.

“As a result of the protocol and that coordination in those events where social media platforms have been used to broadcast attacks, the circulation of those videos had been far, far diminished,” she said.

The man accused of the attacks, 29-year-old Australian white supremacist Brenton Tarrant, is due to stand trial in June on charges of terrorism, murder and attempted murder. If found guilty, he would face a sentence of life imprisonment.