On September 23, 1972, then-Defense Minister Juan Ponce Enrile was ambushed while en route home. This assassination attempt together with the general citizen disquiet, were used by Marcos as reasons to issue Presidential Proclamation No. 1081, proclaiming a state of martial law in the Philippines on September 21. The assassination attempt was widely believed to have been staged; Enrile himself admitted to the assassination attempt to have been staged but he would later retract his claim. Rigoberto Tiglao, former press secretary and a former communist incarcerated during the martial law, argued that the liberal and communist parties provoked martial law imposition. Facing further criticism, Marcos claimed that his declaration of Martial Law was supported by esteemed Philippine statesman Senator Lorenzo Tañada, who at the time was abroad representing the Philippines at international parliamentary conferences. Upon hearing the claim, Senator Tañada debunked it and clarified that he gave no such support for the declaration. Enrile said that "The most significant event that made President Marcos decide to declare martial law was the MV Karagatan incident on July 1972. It was the turning point. The MV Karagatan involved the infiltration of high powered rifles, ammunition, 40-millimeter rocket launchers, rocket projectiles, communications equipment, and other assorted war materials by the CPP-NPA-NDF on the Pacific side of Isabela in Cagayan Valley." The weapons were shipped from Communist China which at that time was exporting the communist revolution and supported the NPA's goal to overthrow the government.