The United States has voiced deep concern over the health of a Ukrainian pilot detained in Russia after her capture by pro-Russian rebels in eastern Ukraine.
Nadia Savchenko has been on a hunger strike since December 13 and is "gravely ill due to her continued detention by Russia," said State Department spokeswoman Jen Psaki.
Calling for Savchenko's immediate release, Psaki said the pilot had been captured in June in eastern Ukraine and "illegally transferred to Russia by the separatists."
The arrest of Savchenko, 33, in August has become a rallying cause in her homeland. She was elected to the national parliament in absentia in elections in October.
Her lawyer told AFP earlier this month that Savchenko had lost some 12 kilograms and was being held on charges of being involved in the killing of two Russian journalists in eastern Ukraine, charges she strongly denies.