 Domestic defence is the responsibility of the all @-@ volunteer military of Bulgaria , consisting of land forces , navy and air force . The land forces consist of two mechanised brigades and eight independent regiments and battalions ; the air force operates 106 aircraft and air defence systems in six air bases , and the navy operates a variety of ships , helicopters and coastal defence measures . Following a series of reductions beginning in 1990 , the number of active troops contracted from 152 @,@ 000 in 1988 to about 32 @,@ 000 in the 2000s , supplemented by a reserve force of 302 @,@ 500 soldiers and officers and 34 @,@ 000 paramilitary servicemen . The inventory is mostly of Soviet origin , such as MiG @-@ 29 fighters , SA @-@ 10 Grumble SAMs and SS @-@ 21 Scarab short @-@ range ballistic missiles . By 2020 the government will spend $ 1 @.@ 4 billion for the deployment of new fighter jets , communications systems and cyber warfare capabilities . Total military spending in 2009 cost $ 819 million . 
