. ▁On ▁ 1 ▁March , ▁Bulg aria ▁joined , ▁and ▁the ▁next ▁day , ▁German ▁troops ▁entered ▁Bulg aria ▁from ▁Roman ia , ▁closing ▁the ▁ring ▁around ▁Y ug oslav ia . ▁ ▁Further ▁pressure ▁was ▁applied ▁by ▁Hitler ▁on ▁ 4 ▁March ▁ 1 9 4 1 , ▁when ▁the ▁Y ug oslav ▁reg ent , ▁Prince ▁Paul , ▁visited ▁Ber ch tes g aden , ▁but ▁the ▁prince ▁delayed ▁a ▁decision . ▁On ▁ 6 ▁March , ▁the ▁Royal ▁Y ug oslav ▁Army ▁Air ▁Force ▁( , ▁V V K J ) ▁was ▁secret ly ▁mobil ised . ▁The ▁following ▁day , ▁British ▁troops ▁began ▁landing ▁in ▁Greece ▁to ▁bol ster ▁the ▁country ' s ▁def ences ▁against ▁the ▁It ali ans . ▁On ▁ 1 2 ▁March , ▁the ▁V V K J ▁began ▁dispers ing ▁to ▁auxili ary ▁air fields . ▁By ▁ 2 0 ▁March , ▁the ▁V V K J ' s ▁dispers al ▁had ▁been ▁completed . ▁Hitler , ▁wish ing ▁to ▁secure ▁his ▁southern ▁fl ank ▁in ▁anticip ation ▁of ▁Germany ' s ▁imp ending ▁invasion ▁of ▁the ▁Soviet ▁Union , ▁demanded ▁that ▁Y ug oslav ia ▁sign ▁the ▁P act . ▁On ▁ 2 5 ▁March , ▁the ▁Y ug oslav ▁government ▁comp lied . ▁Two ▁days ▁later , ▁a ▁group ▁of ▁V V K J ▁and ▁Y ug oslav ▁Royal ▁Guard ▁officers , ▁led ▁by ▁Brig ad ier ▁General ▁Bor ivo je ▁M irk ović , ▁de posed ▁Prince ▁Paul ▁in ▁the