"If you continue on this path [of producing a nuclear bomb] you will find yourself labelled as a ‘rogue state,’ similar to North Korea or Iran. Does Ukraine want to join them?" she said.

According to Gottemoeller, a nuclear-armed Ukraine would lose the leading role it is playing in the world in the field of nuclear non-proliferation, as well damage its image as a reliable partner.

In addition, according to the under Secretary ofsState, Ukraine will not receive "a minimum of added value to its security."

"Quite the opposite. The implications of such changes for Ukraine will be simply disastrous," Gottemoeller said.