US President Donald Trump said Tuesday he would speak very soon with Russian President Vladimir Putin over the reported plague death of a laboratory technician, as Washington pressured Moscow for transparency.
Russian authorities denied that they were imposing anti-plague measures and played down the reports of an incident at an anti-plague institute in Siberia's Irkutsk region last week.
But Washington is showing growing concern, with Secretary of State Marco Rubio calling on Russia to be open about the situation.
"We encourage Russia to be transparent and share more information with the world so that all of us could react accordingly and appropriately," Rubio said during a trip to Iceland.
"Depending on what we learn about it, we would learn how to respond."
Trump later said he would be speaking to Putin about what happened.
"I have a call scheduled, yes," Trump told reporters at the White House when asked if he had spoken to Putin on the issue yet, adding that it would happen "very soon."
The Wall Street Journal reported that the US State Department had sent Russia a confidential diplomatic communication known as a demarche warning Moscow that failure to disclose details runs counter to its international health obligations.
- Cause of death 'undetermined' -
Russian news outlet People of Baikal reported Friday that the dead woman -- named as 28-year-old Darya Shipilova -- may have contracted pneumonic plague from a broken test tube.
Other media reported a possible link between her death and a lab accident at the facility.
The People of Baikal outlet also said up to 200 people with whom she may have had contact were under quarantine.
But Russian authorities say the cause of death is not confirmed and health watchdog Rospotrebnadzor has denied claims circulating in a document online that special measures had been put in place.
"We wish to clarify that the document and information in question do not originate from official sources and are untrue," it said on Telegram.
Russian officials said postmortem tests had not detected the disease.
Irkutsk Regional Governor Igor Kobzev said Monday that a Rospotrebnadzor inspection had found the woman died of pneumonia and the cause was "undetermined".
"No microorganisms linked to the young woman's professional work were found in her biological samples," he said, adding that no other staff at the institute had sought medical attention since her death.
The World Health Organization said that an update received Tuesday from Russia stressed that "no case of this dangerous disease has been recorded in the city of Irkutsk."
The update said Russia had launched an epidemiological investigation into a "case of community-acquired pneumonia" in an employee at the Irkutsk institute, and had identified contacts and made arrangements for medical monitoring and laboratory testing.
"Test results showed no presence of dangerous infectious disease pathogens in any of the contacts," the update said, according to WHO.
- 'Moderate to low' risk -
The United Nations health agency meanwhile said there was a "moderate to low" risk for Irkutsk based on the available information, spokesman Christian Lindmeier said in Geneva, adding it was monitoring the situation closely.
Plague is a bacterial disease that can occur in several forms, including pneumonic plague, which is the most contagious type and can be transmitted by respiratory means. Bubonic plague is transmitted by infected fleas.
Pneumonic plague, which causes lung failure, can be fatal if not treated early, according to WHO.
Trump had said Monday he was ready to help Russia if needed.
But in an apparent response to Trump's offer, the Russian watchdog said Tuesday that Moscow was prepared to assist the United States in combating its own outbreaks of infectious diseases.
It highlighted among other things a "significantly worsened" measles situation in three US states, and a "fatal case of plague" recorded in New Mexico in June.
Measles cases have increased under the Trump administration, in which vaccine skeptic Robert F. Kennedy Jr serves as health secretary.
Meanwhile an international conference on plague and other infectious diseases will be held in Irkutsk on October 21-22, although organizers said it was "unrelated to the recent death of an employee of the anti-plague institute."
