A State Department spokesperson told CNN on Sunday that the US is working with the Centers for Disease Control and Prevention on the matter.
"We are monitoring the situation closely with the CDC and our other interagency partners," the spokesperson said. "We encourage Russian authorities to share accurate information quickly and openly", he added.
The White House is also aware of the case and weighing its options, Axios reported, citing a Trump administration official.
Daria Shipilova, 28, worked at a research institute in Russia's Irkutsk region that deals with plague. Local media, cited by Axios, reported that she broke a test tube containing the pneumonic plague pathogen on 25 September.
She was hospitalised four days later with severe pneumonia and died overnight on 1-2 October.
Russian media have suggested she may have contracted plague, but health authorities have not confirmed that. Russia's public health agency said she had "pneumonia of unknown aetiology" and that further tests found no micro-organisms linked to her work.
Several medical facilities in the region were placed under quarantine, and about 200 people who had contact with her are under medical observation.
Regional governor Igor Kobzev said none of them has shown symptoms and all test results were negative. The health agency said the epidemiological situation in the region remains stable.
Russia's last recorded plague case was in 2016. The disease remains present in Mongolia, including areas near the Russian border.
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Source: PAP