"Over the coming weekend, the ISS crew will self-isolate in the Russian segment of the station to search for an atmospheric leak at the station. The crew will regularly perform all planned operations, nothing threatens the crew's safety," the representative said.
Earlier in the day, US astronaut Christopher Cassidy wrote on Twitter that the ISS crew would "try again with the module isolation this weekend," as the search for a source of the oxygen leak had not yet yielded results. The crew took the same measure in August, when they self-isolated in the Russian module Zvezda for four days.
According to NASA, the leakage was first detected back in September of last year, but its intensity increased only recently. While it still poses no threat to the crew, works were launched to find the source — presumably a 0.1 millimeter (0.04 inch) hole in one of the US modules.
Apart from Cassidy, the current ISS crew includes Russian cosmonauts Anatoly Ivanishin and Ivan Wagner.