WASHINGTON: 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 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.