UNITED NATIONS (AP) -- Ukraine's deputy foreign minister said Friday he fears an imminent Russian invasion.
"We have the information we are in danger," Danylo Lubkivsky told reporters at the United Nations.
He spoke as an official in Ukraine confirmed that pro-Russian forces had detained a team of military observers with the Organization for Security and Cooperation in Europe. The official said the team would be released after further investigation.
Lubkivsky said 20 members had been taken and called it shocking and unprecedented. "We demand to release hostages," he said.
Tensions have spiked as Russia increases military exercises along the Ukraine border. Lubkivsky called it a "very dangerous development" and demanded that Russia withdraw its troops.
"We are going to protect our motherland against any invasion," Lubkivsky said. "We call on the Russians to stop this madness."
Stephane Dujarric, spokesman for the U.N. secretary-general, told reporters earlier Friday that Ban Ki-moon had been reaching out to both countries.
"I think we all have to realize here that the stakes are extremely high, with potential negative implications for peace and security that extend far beyond the eastern Ukrainian cities," Dujarric said. "It would be a grave mistake in the secretary-general's views for any party to turn to military means in an attempt to resolve political issues that can and must be addressed by peaceful means."