Begin had meanwhile boarded the "Altalena", which was headed for Tel Aviv where the Irgun had more supporters. Many Irgun members, who joined the IDF earlier that month, left their bases and concentrated on the Tel Aviv beach. A confrontation between them and the IDF units started. In response, Ben-Gurion ordered Yigael Yadin (acting Chief of Staff) to concentrate large forces on the Tel Aviv beach and to take the ship by force. Heavy guns were transferred to the area and at four in the afternoon, Ben-Gurion ordered the shelling of the "Altalena". One of the shells hit the ship, which began to burn. Yigal Allon, commander of the troops on the shore, later claimed only five or six shells were fired, as warning shots, and the ship was hit by accident.