In the north the FNLA began a major offensive, their ranks bolstered by hired western mercenaries and Zairian soldiers and artillery.  The CIA and China also provided the FNLA with generous military aid in the form of money and arms.  The MPLA continued to receive arms shipments from the Soviet Union and in May recruited the fiercely anti-Mobutu Katangese rebels who had previously served the Portuguese as counterinsurgency troops.  The FNLA offensive reached the outskirts of Luanda, but was stopped by the arrival of 1,500 Cuban soldiers and additional Soviet weapons in August.