By Johan Ahlander

STOCKHOLM (Reuters) - Sweden is reviewing its communication systems for emergency and security services because of tensions in the Baltic region that have been heightened by Russia's actions in Ukraine, Defence Minister Peter Hultqvist told Reuters.

The government canceled a frequency auction for telecom operators at the last minute at the end of October, saying the frequency band might have to be used for public safety services.

The 700-MHz band was previously used for television broadcasts but had been cleared for use by telecoms firms in order to provide better cellphone and mobile broadband connectivity in the Swedish countryside.

Hultqvist said a rise in the number of military exercises and intelligence operations in the region, as well as Russia's annexation of Crimea and the conflict in eastern Ukraine, had increased the need for better and more secure communications systems.

"It is clear that the security situation has changed for the worse," he said in a telephone interview.

"We must ensure that the operators involved in public safety, security, health and defense are able to communicate and exchange information in a efficient and secure way."

Tension in the Baltic region has been rising for several years. Late last month Russian media reported that the country is sharply upgrading the firepower of its Baltic Fleet by adding warships armed with long-range cruise missiles.

Russia blames escalated activity by NATO members for the increased tension. NATO leaders have reinforced the defense of Poland and the former Soviet Baltic states of Latvia, Lithuania and Estonia because of Moscow's takeover of Crimea and its support for Ukrainian separatists.

Sweden, which is not a NATO member, scrambled to mount its biggest submarine hunt since the Cold War in 2014 when the military said there were several credible sightings of possible Russian vessels. Neighbouring Finland has complained of several air space violations by Russian fighter jets.

(Reporting by Johan Ahlander; Editing by Mark Trevelyan)