Anti-government protesters staged their latest noisy procession in Bangkok early Thursday, amid heightened tension in the run-up to Sunday’s general election.

Several thousand protesters, many blowing whistles, marched along the capital’s busy central Sukhumvit Road, calling on caretaker Prime Minister Yingluck Shinawatra to resign and urging a poll boycott.

Protest leader Suthep Thaugsuban has vowed to “completely shut down” the capital on election day.

The protesters say Yingluck’s government is illegitimate and controlled by her brother Thaksin, who was deposed as premier in a 2006 military coup. He lives in Dubai to avoid a two-year jail term for abuse of power.

Suthep is demanding the government step down in favour of an appointed council of rulers, and that legal and political reforms take place before an election is held.

The protests have some support from the main Opposition Democrat Party, which is boycotting Sunday’s polls.

Yingluck’s Pheu Thai party, which enjoys strong support in the north and north-east of the country, is widely expected to win comfortably.

But an investigation into her role in a government rice subsidy programme could leave her facing possible impeachment.

Mass protests against the government over the past three months have left 10 people dead and more than 570 injured.