Ukrainian diplomats have visited a Ukrainian teenager held in Russian custody on terrorism-related charges for the first time since his arrest.
Ukrainian Foreign Ministry spokeswoman Maryana Betsa wrote on Twitter that Ukrainian consuls visited Pavlo Hryb on September 18.
Betsa said that Ukrainian physicians have not been allowed to examine Hryb.
"We demand doctors' access," she wrote.
Hryb's father, Ihor Hryb, said earlier that his son has a medical condition, which he did not specify, and needs special treatment and drugs on a regular basis to avoid a possible hemorrhage.
Hryb, 19, went missing in late August after he traveled to Belarus to meet a woman he met online in what his relatives believe was a trap set by Russia's Federal Security Service (FSB).
The FSB subsequently informed Kyiv that Hryb was held in a detention center in Russia on suspicion of abetting terrorism, without giving any details.
Ihor Hryb has said his son was openly critical of Russian interference in Ukraine on social media.
The Ukrainian Foreign Ministry on September 8 protested Hryb's detention and demanded that Moscow grant consular access to the teenager "and explain in detail all of the reasons for his detention."
The ministry condemned what it called Russia's "persecution of Ukrainian citizens in Russia and elsewhere, groundless detentions of Ukrainians, violation of their rights to have fair trials, and their convictions on fabricated and politically motivated charges."
Kyiv and Moscow have been locked in a standoff over Russia's seizure of Ukraine's Crimean Peninsula in March 2014 and Moscow's backing of armed separatists in a war that has killed more than 10,000 people in eastern Ukraine since April 2014.