Ukraine's Greek Catholic Church said a priest was seized by armed men from a chapel in Sevastopol on Saturday, shortly after a pro-Russian group reported one of its leaders had been abducted.
The two incidents are the latest in a series of kidnapping reports in Crimea, often involving activists for and against the referendum to be held on Sunday to decide whether the region should break away from Ukraine and join Russia.
Father Mykola Kvich, a chaplain with Ukraine's armed forces, was taken from a parish near the city cemetery, the Church said.
But according to local police, the priest was detained and later released, and 10 bullet proof vests were found in his residence during a search.
The Greek Catholic Church is particularly strong in the mostly Ukrainian-speaking west of the country and has been in favour of the Maidan protests that brought the current pro-West government in Kiev to power last month.
The priest's chaplain role "could be the reason for these actions by the armed self-defence groups in Crimea," said Father Lyubomyr Yavorskiy, an official in the Church's military chaplaincy department.
Earlier Saturday a pro-Russian leader in Sevastopol -- home to Russia's Black Sea Fleet since the 18th century -- was reported kidnapped.
The Russky Blok party cited eyewitnesses saying that its leader in the city, local assemblyman Gennadiy Basov, "was seized by nine people and taken away in a blue minivan".
Repeated attempts to contact Basov on his mobile went unanswered and police said they were "checking" a formal missing person report from the party.
Kidnapping reports are often hard to confirm because Ukraine's interior ministry no longer has authority in Crimea, and the reports sometimes appear to be part of an "information war" between two bitterly opposed sides.
Three activists and journalists were reported missing after being last seen at a Crimean-controlled checkpoint earlier this week and have since been released.
One of them, Olena Maksimenko, said the experience was "psychologically tough".
"They were trying to find out who we worked for and who was paying us," she said at a press conference in Kiev.
Maksimenko said at one point she was throttled with a rope and punched in the face by a Cossack.
She said they were arrested at a checkpoint and taken to a military base in Sevastopol.
"They regularly took us out for interrogations, tried to get me to say I was some kind of spy," she said.
Ukraine's former defence minister Anatoliy Gritsenko said Friday on his Facebook page that his son Oleksiy was one of three pro-unity activists who went missing on Thursday in the Crimean capital Simferopol.
Gritsenko said his son had been supplying food, medicine and electricity generators to Ukrainian military bases on the peninsula, which are often surrounded by self-defence groups and Russian forces.
Amnesty International said it was following the case and that two of the activists' mobile phones had been tracked to near Simferopol's military commissariat.
The human rights watchdog in a statement called on Crimean authorities to ensure "their immediate and unconditional release".
"Reports of the harassment and intimidation of activists and journalists by the de facto military forces operating in Crimea are an extremely worrying development where human rights abuses are already rife," said John Dalhuisen, the group's Europe and Central Asia director.
Asked about these and other reports of abductions, Crimea's pro-Moscow prime minister Sergiy Aksyonov told reporters on Friday that any detentions were aimed at fighting off "provocateurs".
"I'm not arresting anyone but if people come here with bad intentions then law enforcement will deal with them," he said.