Simon Ostrovsky, an American journalist working for Vice News seen here, has been detained in Ukraine, according to reports.

At a news conference in Slaviansk Tuesday, the self-declared mayor and pro-Russia separatist leader confirmed the detention but did not name the journalist.

(SOUNDBITE) (Russian) SELF-DECLARED MAYOR OF EASTERN UKRAINIAN CITY OF SLAVIANSK, VYACHESLAV PONOMARYOV, SAYING:

"A journalist has been detained, as I understand. To be honest, I didn't have time this morning to solve this problem and meet him to talk to him. What can I say? We have our own documents, our own leads that point to people who are unwanted here in our city. If we find those people, obviously we detain them, we talk to them, and only then we can figure out how dangerous they are for us and our town's residents."

Vice News identified Ostrovsky on its website, saying it was working to secure his safety.

Ostrovsky has been reporting in Ukraine for weeks, filing video dis