HELSINKI (Reuters) - Finland and Sweden will buy portable firearms and anti-tank weapons together, Finland's defence ministry said on Wednesday, as the two Nordic country's handed in their applications to join the Western military alliance NATO.

       The two countries will step up their cooperation in defence procurement by Finland joining an agreement to acquire anti-tank weapons from Swedish weapons maker Saab Dynamics, a subsidiary of Saab, the ministry said.

       Finland's defence minister Antti Kaikkonen also authorised preparations for a joint purchase of small fire arms including assault rifles, shotguns and arms for personal protection, the ministry said.

       Russia's invasion of Ukraine prompted Finland and Sweden to apply to join NATO.

       The agreement for anti-tank weapons enables purchases of missiles, recoilless rifles, ammunition and other related equipment, it said, adding the purchases are pending separate investment decisions.

       "Joint procurement made possible by the enforcement documents will improve the availability of critical defence equipment in Finland and Sweden as the countries will be able to operate through the same commercial agreement," it said.

       (Reporting by Anne Kauranen; editing by Grant McCool)