Bahrain stages by-elections Saturday boycotted by the main Shiite opposition bloc, with pro-democracy protesters vowing to escalate their actions six months after an uprising in the kingdom was crushed. The elections are for 18 seats left vacant in the 40-member parliament after MPs from Al-Wefaq, the Gulf state's largest opposition group, quit in February in protest over a crackdown by security forces on peaceful demonstrators. Bahraini authorities later allowed protesters, mostly Shiites, to camp out at Manama's central Pearl Square until security forces, boosted by a Saudi-led Gulf regiment, drove them out in a deadly crackdown in mid-March. In total, 55 candidates will compete for 14 seats. "Four candidates were already declared winners after their competition withdrew," an Information Affairs Authority statement said. The main challenge lies in whether 187,000 eligible voters will respond to appeals by the authorities and turn out in Shiite-majority areas, after Al-Wefaq said last month it would boycott the election. The government has considered sanctions against those who do not vote, threatening to exclude them from government jobs and deny them public services, the pro-government Al-Ayyam daily reported on Wednesday. Al-Wefaq, or the Islamic National Accord Association, in a statement called the measures "terrorising" and "an organised crime project that contradicts basic principles of humanity and freedom of opinion and expression." It joined a national dialogue in July at the initiative of the king to relaunch political reform in Bahrain, which is ruled by the Sunni Al-Khalifa dynasty, but soon pulled out and rejected the process's outcomes. Al-Wefaq has not called for the Al-Khalifas to be overthrown, but has stuck to its main demands for a fully fledged constitutional monarchy with an elected government and powerful parliament, as well as an independent judiciary. It also disputes the legitimacy of parliament's upper house, whose 40 members are appointed rather than elected and which can block initiatives by the lower house. The new post-election parliament will vote into legislation projects agreed upon in the national dialogue, the government said on Wednesday. "Parliament will have more powers following agreements made by the national dialogue... (which) has reached agreement on about 200 key political, economic and human rights issues," said an English-language statement. Al-Wefaq insists that the dialogue did not represent the will of the people. In June, King Hamad announced the lifting of the state of emergency declared in mid-March, and later formed The Bahrain Commission of Inquiry -- an independent panel of foreign experts -- to investigate the month-long unrest. Authorities say 24 people were killed in the unrest, including four policemen. The opposition puts the death toll at 30. Other measures announced this week include a "National Victims' Compensation Fund" and an additional budget outlay of more than one billion dollars over two years to improve living standards in the tiny kingdom, the poorest among its oil-rich Gulf neighbours. Al-Wefaq head Ali Salman, speaking on Thursday during a gathering of thousands in a Shiite suburb of Manama on "a day of national unity" between Sunnis and Shiites, has declared Saturday's polls a "day to mourn democracy." Activists have called for marches on Friday and Saturday towards Pearl Square, symbol of the protests earlier this year. As tension soared in Bahrain, home to the US Fifth Fleet, US President Barack Obama's pick for ambassador urged the kingdom Wednesday to avoid "repression." "Political reform and respect for human rights are vital to Bahrain's stability and to the protection of US interests in the region," Thomas Krajeski told a Senate Foreign Relations Committee confirmation hearing. "Bahrain's long-term stability depends on addressing domestic grievances not through repression, but through genuine reform and reconciliation."