Ukraine's National Union of Journalists (NUJ) has appealed to international foreign missions asking their help to determine the fate of blogger Stanislav Aseyev, who disappeared in Donetsk.

"NUJ asks representatives of foreign missions in Donetsk to help determine the whereabouts of 27-year old blogger Stanislav Aseyev, whose work was published in Ukrainian media under the pseudonym Stanislav Vasyn," reads the note, which was posted on the NUJ chief Serhiy Tomilenko's Facebook page on Sunday.

The post says NUJ does not have any official representatives in temporarily occupied areas of eastern Ukraine and therefore had requested assistance from the OSCE monitoring mission in Donbas, as well as the OSCE's media representative based in Vienna.

The NUJ wants to find out the whereabouts of Aseyev and, if he has been arrested, what charges have been made against him, whether he has access to legal counsel. NUJ also is interested whether Aseyev has been wounded and received medical attention, or if he has been allowed a visit from his mother.

The Kyiv office of International Committee of the Red Cross has received a copy of the request and promised to make inquiries through its representatives in Donetsk.