The Hamas-run government in Gaza suspended the work of the Palestinian Central Elections Commission on Monday, a day before it was to start registering new voters, abruptly halting one of the few tangible steps toward reconciliation with the rival Fatah party, based in the West Bank. The move pushed off the prospect of presidential and parliamentary elections. Though considered long overdue, no date had been set for them. The latest delay added a new complication in a reconciliation process that began more than a year ago with an accord brokered by Egypt that was described as historic but has mainly resulted in new rounds of talks, more documents and broken deadlines.