The government in Kiev has asked Ukraine's Western allies to supply warships and submarines in addition to battle tanks.
"We would need warships so that the coast can be protected, we have a very long coast. We would also need submarines to avert the danger of a new attack from the sea in the Black Sea," Deputy Foreign Minister Andriy Melnyk told the German television channels RTL and ntv on Wednesday.
The battle tanks that have been promised to fight off the Russian invasion should only be the first step, Melnyk said.
"We have a very powerful opponent, the Russians are producing weapons at full speed." He added that the war was far from over.
Earlier, Melnyk had said that Ukraine also needed reinforcements for its air force. Germany could help with Tornados or Eurofighters, for example, Melnyk said. He demanded "leadership" from German Defence Minister Boris Pistorius on this point.