At least two explosions blew up a bus in Tel Aviv today, wounding at least 13 people. The blast occurred while Palestinian President Yasser Arafat and Egyptian President Hosni Mubarak held talks in Cairo on U.S. proposals for Israeli-Palestinian peace. The Cairo meeting is taking place instead of an expected summit between Arafat and Israeli Prime Minister Ehud Barak hosted by Mubarak. Egyptian state television said the three-way summit had been delayed because of what it called a wide difference in the Palestinian and Israeli view of President Clinton’s proposals. The Palestinians are most opposed to requirements that they scale back the right of return for millions of refugees.