 During the entire period of 1970 – 74 , FRELIMO intensified guerrilla operations , specialising in urban terrorism . The use of landmines also intensified , with sources stating that they had become responsible for two out of every three Portuguese casualties . During the conflict , FRELIMO used a variety of anti @-@ tank and anti @-@ personnel mines , including the PMN ( Black Widow ) , TM @-@ 46 , and POMZ . Even amphibious mines were used , such as the PDM . Mine psychosis , an acute fear of landmines , was rampant in the Portuguese forces . This fear , coupled with the frustration of taking casualties without ever seeing the enemy forces , damaged morale and significantly hampered progress . 
 During the entire period of 1970 – 74 , FRELIMO intensified guerrilla operations , specialising in urban terrorism . The use of landmines also intensified , with sources stating that they <a href='been_done' title='1'><mark>had</mark></a> become responsible for two out of every three Portuguese casualties . During the conflict , FRELIMO used a variety of anti @-@ tank and anti @-@ personnel mines , including the PMN ( Black Widow ) , TM @-@ 46 , and POMZ . Even amphibious mines <a href='uninflect' title='2'><mark>were</mark></a> used , such as the PDM . Mine psychosis , an acute fear of landmines , was rampant in the Portuguese forces . This fear , coupled with the frustration of taking casualties without ever seeing the enemy forces , damaged morale and significantly hampered progress . 
Durin the entire period of 1970 – 74 , FRELIMO intensified guerrilla operations , specialising in urban terrorism . The use of landmines also intensified , witt sources stating dat they done become responsible fir two out of every three Portuguese casualties . Ddurinthe conflict , FRELIMO used a variety of anti @-@ tank and anti @-@ personnel mines , including the PMN ( Black Widow ) , TM @-@ 46 , and POMZ . Even amphibious mines was used , such as da PDM . mines psychosis , an acute fear of landmines , was rampant in the Portuguese forces . This fear , coupled w/ tdafrustration of taking casualties w/o ever seeing the enemy forces , damaged morale and significantly hampered progress .