Egyptian President Hosni Mubarak on Thursday received a phone call from Israeli Prime Minister Ariel Sharon, who apologized for the killing of three Egyptian soldiers by Israeli tank fire mistakenly, the official MENA news agency reported. The soldiers, who were at the Rafah area on the Egyptian- Palestinian border, were killed after an Israeli tank fired one shell at them by mistake. Israeli reports said the Israeli tank crew, operating near the Philadephi Route in the Rafah area, apparently thought the three to be Palestinians smuggling weapons. The tank then fired a shell across the border before dawn and killed the three, a senior Israeli security source told the Israeli newspaper Ha'aretz. "Three Egyptian troops were killed," the source said, "our tank thought they were Palestinian weapons smugglers." The Israeli Foreign Ministry will join senior defense officials in an immediate investigation into the incident.