STOCKHOLM (Reuters) - Sweden's military said on Thursday it was ramping up its visible activities on the Baltic Sea island of Gotland due to increased tensions between NATO and Russia over Ukraine.

       Moscow has spooked the West by massing troops near Ukraine, sparking fears that it is considering invading. Moscow denies any such plans, saying it can deploy forces on its territory however it chooses.

       Gotland, Sweden's biggest island, is strategically important and lies around 330 kilometres (205 miles) from Kaliningrad, the headquarters of Russia's Baltic Fleet. In 2019 Sweden deployed an updated ground-to-air missile defence system on the island.

       "From today, we will have patrols out that will be visible in certain places, including in (the city of) Visby," Gotland regiment spokesperson Tomas Angshammar said.

       Sweden is not a NATO member but has close ties to the Atlantic alliance and has been beefing up its armed forces after decades of neglect amid increased anxiety over Russian sabre-rattling in the Baltic Sea region.

       Stockholm has in recent years complained over several incidents involving Russian military planes, including violations of Swedish airspace.

       Sweden's top military commander said last week that Sweden's security strategy would be entirely undermined if NATO agreed to refrain from expanding further and to curb some of its activity in Europe, as Russia has demanded.

       (Reporting by Helena Soderpalm and Anna Ringstrom; Editing by Gareth Jones)