US Defence Secretary Leon Panetta was headed to Cairo from Tel Aviv on Tuesday in an effort to defuse tensions between Egypt and Israel that have mounted since the end of Hosni Mubarak’s rule. Before flying out after a one-day visit to Israel, Panetta said he will seek to encourage both sides to ease friction over the Sinai incident and will ask Egypt’s military rulers to release an alleged Israeli spy. Ilan Grapel, a US-Israeli dual national, has been charged with being an agent of Israel’s Mossad intelligence service and of sowing sectarian strife in Egypt during the uprising Mubarak’s ouster. He has been in custody since June 12. Relations between Egypt and Israel, which have been bound by a peace treaty since 1979, have entered a turbulent period since Mubarak’s overthrow, coinciding with uprisings across the Arab world that could give greater voice to popular anger over Israel’s treatment of the Palestinians. Panetta expressed concern that Israel was “increasingly isolated” in the diplomatic arena and needed to work to shore up its relations in the region, particularly with Egypt and Turkey. Israel has said an attack on its south in August was mounted from the Egyptian territory and has expressed concern that a “security vacuum” has developed there since Mubarak’s fall. In Cairo, Panetta is also due to discuss Egypt’s plans for elections and a transition to a civilian-led govt in talks with Egypt’s military ruler Field Marshal Hussein Tantawi and Prime Minister Essam Sharaf. The Pentagon chief planned to reassure Cairo of Washington’s commitment to the two govts’ longstanding security ties.