In the lead-up to the elections, on 26 September 2005 Israel launched a campaign of arrests against PLC members. 450 members of Hamas were detained, mostly those involved in the 2006 PLC elections. The majority of them were kept in administrative detention for different periods.[23] In the election period, 15 PLC members were captured and held as prisoners.
During the elections, the Israeli authorities banned the candidates from holding election campaigns inside Jerusalem. Rallies and public meetings were prohibited. The Jerusalem identity cards of some PLC members were also revoked. The Carter Center, which monitored the elections, criticised the detentions of persons who “are guilty of nothing more than winning a parliamentary seat in an open and honest election”.
Israeli obstruction during the election resulted in estimated 123,000 voters in East Jerusalem being prevented from registering until ten days before the elections, creating a number of logistical problems shortly before the election day. The checkpoints of Israel also continued to pose serious obstacles to all Palestinian parties during the electoral campaign as well as on voting day itself. It was/is also noted that Palestinian refugees in exile and 9,000 prisoners remained ineligible to vote.
Voting in East Jerusalem
On 21 December 2005 Israeli officials stated their intention to prevent voting in East Jerusalem, which, unlike most of the Palestinian-inhabited areas that were planned to participate in the election, was under Israeli civil and military control. (Israel annexed East Jerusalem in the wake of the Six-Day War; this move was not recognized by most other governments, or by the PNA, which claims Jerusalem as a Palestinian capital.) Israel’s stated motivation was not the argument about sovereignty over the area (Palestinian voters in East Jerusalem had been allowed to vote in previous PNA elections despite the dispute) but concern over Hamas’ participation in—and potential victory in—the election.
Ref: Wikipedia