REUTERS/Konstantin Chernichkin
"No one will give up Crimea to anyone," Yatseniuk told reporters.
The isolated Black Sea peninsula, which is part of Ukraine but has a majority Russian population, is currently occupied by pro-Russian gunman and Russian troops.
There are now fears that the Kremlin, which is Ukraine's ousted president and had not recognized Yatseniuk's government, will now move more troops into Ukrainian territory. There are currently more than 6,000 Russian troops in Crimea.