The energy crisis in Sweden is getting worse: the shutdown of its largest nuclear reactor puts the country at real risk of rolling blackouts, Swedish Prime Minister Ulf Kristersson said, Reuters reported.

Uniper SE will close its unit Oskarshamn-3 on the southeastern coast of the country for a nine-day maintenance break, which will aggravate the power shortage. According to the grid operator, Sweden will have to rely on imports from Norway, Germany and Poland next week to provide enough electricity.

The situation is relatively acute, we don't want to sow panic, but this is a serious problem and there are significant risks, Kristersson said.

Southern Sweden is the region in all of Europe with the least production capacity compared to demand.

Sweden's energy crisis has been exacerbated by the prolonged shutdown of Vattenfall AB's Ringhals-4 reactor, which is not operating until Feb. 23. Nuclear power is vital to keep the largest economy in the Nordic region running.