JERUSALEM, Jan 19 (Reuters) - Israel transferred $100 million in withheld Palestinian tax revenues to President Mahmoud Abbas on Friday, part of a U.S.-led push to bolster the moderate leader, Israeli officials said. The transfer was the first by Israel since Hamas, whose charter calls for the Jewish state's destruction, came to power last year. The United States has been pressing Israel to take steps to help strengthen Abbas of Fatah in his power struggle with Hamas Islamists.