Reuters contributed to this report.An IDF soldier has been killed by cross-border gunfire from Lebanon while driving in an army vehicle on Sunday night. He has been named as 31-year-old St.-Sgt. Maj. Shlomi Cohen, from Afula.Cohen, an officer from the Israel Navy, was carrying out an official mission near an IDF border post in the Rosh Hanikra region, and was driving some 50 meters away from the border, when six to seven shots struck him and the jeep, critically injuring him. Paramedics rushed Cohen to the Nahariya Hospital for the Western Galillee, but he succumbed to his injuries soon afterwards.After the shooting, IDF soldiers spotted suspicious figures on the Lebanese side of the border, and opened fire at them. An IDF source said it was not immediately clear if there were casualties on the Lebanese side of the border as a result.An initial IDF assessment, based on data from lookout positions on the border, found that Cohen was hit by shots fired by a soldier from the Lebanese Armed Forces, who apparently acted alone."We are sending messages to the United Nations Interim Force in Lebanon (UNIFIL) regarding the severity of this incident. There is no indication that an infiltration into our territory occurred," the army source said on Sunday night. "The IDF is prepared in the North," he warned.The shooting occurred at around 9 p.m. on Sunday.The IDF said in a statement that it is investigating the shooting, adding that it reserved the right to respond at a time and place it sees fit.The source added that several details, such as the identity of the Lebanese soldier, remain currently unknown.Lebanese sources said they had lost contact with the Lebanese soldier after the shooting.UNIFIL spokesman Andrea Tenenti said. said, "We are now trying to determine the facts of what happened and the situation is ongoing.UNIFIL's force commander is in contact with counterparts in the Lebanese and Israeli army, urging restraint."UN Secretary-General Ban Ki-moon said on Monday that both the Israel Defense Forces and the Lebanese military were cooperating with the investigation, though he urged both sides to maintain calm. Cohen will be laid to rest at the Haifa military cemetery on Monday evening.Maj.-Gen. (Res.) Israel Ziv, former head of the Operations Branch in the IDF, told Army Radio on Monday morning that the IDF will have to examine how Cohen was permitted to drive alone at night near the frontier. "The chances of Hezbollah [being responsible] are very low. This does not fit in with their pattern, it's not in their interest, and it didn't occur in an area they are active in," Ziv said. "What was the motivation of the [Lebanese] soldier? All options could be true. The Lebanese army also does not have an interest in this happening," Ziv added. He added that the Lebanese Armed Forces, which has limited capabilities but strong discipline and internal order, will investigate the shooting. Yaakov Biton, a relative of Cohen, described him as a "modest, quiet guy, very dedicated to his wife and daughter." Weeping quietly while speaking to Army Radio, Biton said Cohen leaves behind his wife, Ma'ayan and a daughter who will turn one next month. The young family had bought an apartment and planned to move soon. "All of these plans are gone now," Biton said.