Lithuania's Defense Ministry says NATO jets patrolling the airspace of the Baltic countries scrambled 160 times to intercept Russian planes last year, a 14 percent increase from the year before.

The ministry said Tuesday that the number was up from 140 in 2014 and 47 in 2013, reflecting increased Russian air activities over the Baltic Sea.

Spain and Belgium are taking over NATO's rotating Baltic Air Policing mission this week from Hungary and Germany.

The alliance says the "efforts are focused on stopping incursions into NATO airspace and on preventing acts of air terrorism."