CHARLOTTETOWN -- Next week's scheduled reopening of the Atlantic bubble was cast in serious doubt Tuesday as Nova Scotia announced it was reimposing restrictions for travellers from New Brunswick.

Premier Iain Rankin told reporters he was reversing a decision made March 19: all visitors to Nova Scotia from New Brunswick will have to self-isolate for 14 days as of 8 a.m. on Thursday.

He said his province is concerned about the potential spread of variant cases of the virus in New Brunswick following a recent outbreak in the Edmundston, N.B., area.

"Now we are seeing some variant cases in Saint John and more worrying, we are seeing some cases under investigation in the Moncton area," Rankin said.

The premier said the move is necessary to prevent an outbreak of a more contagious mutation of the novel coronavirus in his province, adding that it was looking "unlikely" the Atlantic travel bubble would be reopened as planned next Monday.

"Right now we are looking at pushing back the opening until sometime in May," he said.

In Charlottetown, Prince Edward Island Premier Dennis King said the reopening of the regional bubble is "precarious."

"All signs are pointing to the fact that we will need to delay," King told reporters. "I know this isn't the news that everyone wants to hear today." King said he expected the four Atlantic premiers would make an official announcement later Tuesday.

The so-called Atlantic bubble was introduced last summer as a way for the region's residents to travel freely between the four provinces without having to isolate for 14 days. But with COVID-19 cases spiking in the rest of Canada, King said the outlook is a lot different now than it was four weeks ago.

"We have been spared, so far, from what is a third wave of this pandemic," he said. "But there is regional evidence in Atlantic Canada that is becoming more and more concerning with each and every day."

The province's chief public health officer, Dr. Heather Morrison, reported no new cases Tuesday.

New Brunswick Premier Blaine Higgs told reporters on Tuesday he agrees the goal of reopening the Atlantic bubble on April 19 is "in jeopardy."

Health officials in New Brunswick are aiming to offer all adult residents at least one dose of COVID-19 vaccine by the end of June, but Higgs said the reopening of the travel bubble likely won't have to wait that long.

"The Atlantic bubble was very successful," Higgs said. "And if we get our numbers back under control here, I wouldn't want to wait until the end of June."

New Brunswick reported four new cases of COVID-19: one in the Saint John region and three in the Edmundston area, which is under lockdown.

In Newfoundland and Labrador, Premier Andrew Furey said he, too, was closely monitoring the situation in New Brunswick.

"Our province continues to weigh all options when it comes to lifting travel restrictions with the other Atlantic provinces," he said in an emailed statement, adding that he expects to have more information after the premiers meet.

Newfoundland and Labrador health authorities reported one new COVID-19 infection Tuesday, bringing the province's active case count to 11.

Meanwhile, Nova Scotia reported six new infections and 45 active cases across the province. Five of the new cases were related to international travel, and the other was linked to domestic travel outside the Atlantic region.

This report by The Canadian Press was first published April 13, 2021.

-- With files by Sarah Smellie in St. John's and Keith Doucette in Halifax.