It was reported by Joinfo.ua with reference to the press service of the U.S. Department of State.
The statement was made by Acting Deputy Speaker of the Department of State Jeff Rathke.
"We reiterate our serious concerns over her treatment in detention and reports that she is gravely ill while she remains a hostage to Russian authorities," said Rathke.
"We call on Russia to release Nadia Savchenko and all other Ukrainian hostages immediately," said Rathke.
Rathke also reminded that the issue of the release of the hostages was Russia's obligations in accordance with the Minsk Agreement signed in September last year, as well as under the plan of implementation of the agreement of February 12, 2015.
Previously, we reported that the investigation in case of Nadiya Savchenko was extended by six months, until November 13, 2015.