Tens of thousands of Malaysians are expected to protest for a second day in Kuala Lumpur, calling for PM Najib Razak to quit over a financial scandal.
On Saturday, crowds were undeterred by a heavy presence of police who had called the protests illegal.
Protesters are angered by a $700m payment made to Mr Razak's bank account from unnamed foreign donors.
He has denied any wrongdoing. He said protesters were tarnishing Malaysia's image.
Police estimated 25,000 people participated in Saturday's demonstration, while Bersih - the pro-democracy group behind the rally - said 200,000 took part at the peak.
Former Prime Minister Mahathir Mohamad made a surprise appearance late on Saturday, telling the cheering protesters to "carry on". He has backed the calls for Mr Najib to quit.
The crowd thinned in the evening, but many slept out on the street in readiness for the second day.
The rally was scheduled to last until midnight on Sunday.
"Those who wear this yellow attire... they want to discredit our good name, scribble black coal on Malaysia's face to the outside world,'' national news agency Bernama quoted Mr Najib as saying.
The main accusation against the prime minister is that he took $700m from the indebted 1MDB, which he established in 2009 to try to turn Kuala Lumpur into a financial hub.
Cabinet ministers have said the money transfers were "political donations" from unidentified Middle Eastern sources, and that there was nothing improper. No further details have been given.
What is 1MDB?
- The 1Malaysia Development Berhad state investment fund was established under Prime Minister Najib Razak in 2009 to transform Malaysia into a high-income economy.
- Critics say the fund overpaid for many of its investments and spent millions on fees to investment bank Goldman Sachs
- It began attracting attention at the end of 2014 when it started missing payments to creditors. It later emerged that the fund was mired in $11bn of debt.
- Mr Najib has been accused of taking $700m from the fund - a charge which he has denied.
- Malaysia anti-corruption commission said it had verified that the money was a donation from unnamed foreign donors.