A Russian court has rejected an appeal to release a Ukrainian pilot who has been on hunger strike since mid-December.

The case of Nadezhda Savchenko has attracted high attention in recent weeks as concerns rise about her health.

Savchenko has been in Russian custody since June on charges that she provided information for a mortar attack that killed two Russian journalists covering the conflict in eastern Ukraine.

Last fall, she was elected a member of the Ukrainian parliament. The appeal that was rejected on Wednesday asked for her to be released in order to attend a session of the Parliamentary Assembly of the Council of Europe.

The assembly's head a day earlier said "time is running out" to save Savchenko's life.