Washington D.C., March 20 - The American delegation to Pope Francis's inaugural mass on Tuesday delivered a letter from US President Barack Obama to the Vatican, American media reported on Wednesday. US Vice President Joe Biden flew back to Washington D.C. on Tuesday after attending the ceremony that launched the new pontificate. The ceremony in which Pope Francis received the fisherman's ring drew high government and religious leaders, heads of state, and an estimated one million religious pilgrims. President Barack Obama did not attend, as he boarded Air Force One on Tuesday to make his first state visit to Israel since taking office. Obama aims to reassure America's top ally in the turbulent Middle East of continued US support and to discuss developments in Syria and Iran, the Associated Press reported on Wednesday. After Israel, the US president will also visit to the Palestinian Authority chief, Mahmud Abbas and Jordan's King Abdullah before leaving on Friday, March 22.